Fertility

Measurement of fertility

Fertility in preindustrial societies

Fertility in industrial countries

Differential fertility

BIBLIOGRAPHY

Demographers distinguish fertility (actual reproduction) from fecundity (the capacity for reproduction). The distinction is important, because in all societies actual reproduction is less, often much less, than the potential maximum. The rather wide variations in actual fertility among societies have no known general relation to differences in fecundity. In specific instances, low fertility may be explained by such biological factors as venereal disease. However, it is likely that group fertility levels vary generally in relation to social factors that affect either the social norms about the proper number of children or a limited number of means of fertility control. These means are intermediate between the social organization or social norms, on the one hand, and actual fertility, on the other hand.

Davis and Blake (1956) have provided the following useful classification of these “intermediate variables”:

Factors affecting exposure to intercourse:

(A) Those governing the formation and dissolution of unions in the reproductive period:

(1) Age of entry into sexual unions.

(2) Permanent celibacy: proportion of women never entering sexual unions.

(3) Amount of reproductive period spent after or between unions.

(a) When unions are broken by divorce, separation, or desertion.

(b) When unions are broken by death of husband.

(B) Those governing the exposure to intercourse within unions:

(4) Voluntary abstinence.

(5) Involuntary abstinence (from impotence, illness, unavoidable but temporary separations).

(6) Coital frequency (excluding periods of abstinence)

Factors affecting exposure to conception:

(7) Fecundity or infecundity, as affected by involuntary causes.

(8) Use or non-use of contraception:

(a) By mechanical and chemical means.

(b) By other means.

(9) Fecundity or infecundity, as affected by voluntary causes (sterilization, subincision, medical treatment, etc.).

Factors affecting gestation and successful parturition:

(10) Foetal mortality from involuntary causes.

(11) Foetal mortality from voluntary causes.

Most of the intermediate variables are regulated by a complex structure of normative prescriptions (Nag 1962; Freedman 1963). For example, how many children a couple should have is a problem so recurrent and with so many social ramifications in each society that it would be a sociological anomaly if appropriate social norms did not develop as a social solution to guide behavior. Moreover, different combinations of values for these variables may produce identical fertility levels, whereas societies or groups with very different fertility levels may have similar values on some of the intermediate variables. Of course, the connection between some of these intermediate cultural variables and a society’s fertility level need not be apparent to members of the society.

Measurement of fertility

Fertility can be defined as the number of births occurring in a population unit during a specified time period. The unit may be the individual male or female, the male-female couple, the social stratum or other groupings of individuals or couples, or the whole society. For any of these levels, birth rates or frequency distributions may be computed separately or adjusted for a large variety of social, economic, or demographic characteristics. In most official statistics, the time period is short, giving a cross-section picture of what happens in a particular year or period. An important departure from cross-section rates is the measurement of fertility over the childbearing span of historical cohorts of women [see COHORT ANALYSIS].

“Period” measures . The most common fertility measure is the crude birth rate, or number of births per thousand population per annum. It is usually computed for whole nations or for major demographic strata within nations, such as the urban population. More refined measures are important for some purposes, but the crude birth rate is still often used in evaluating the contribution of fertility to population growth in relation to mortality and migration. Table 1 shows the considerable variation in crude birth rates among major world regions.

Birth rates are called age-specific when they are computed for fairly narrow age groups (usually one or five years), usually with reference to the female population only. Since the crude birth rate is a function of both the age-sex distribution of the population and of the age-specific fertility rates, various methods are used to eliminate the effect of varying age-sex distributions in a comparison of different populations. This may be done either by standardization (in this case, the use of a common age-sex distribution to weight the different age-specific rates) or by the computation of one of the four remaining measures in common use by demographers:

(1) Births per annum per thousand women in the childbearing years (the general fertility rate).

(2) Births per annum per thousand women in specified age groups (age-specific birth rates).

(3) The gross reproduction rate or “total fertility rate” (a simple summation of the age-specific birth rates for female babies or all babies).

(4) The net reproduction rate(an adjustment of the gross reproduction rate to take into account the effect of mortality on reproduction rates).

These are all “period” measures—that is, measures based on the births and deaths of a particular year or other time period considerably shorter than the reproductive span of the couples in the population. The rates do not take into account the earlier reproductive history of the units measured; they may therefore be misleading about long-run reproductive trends, especially for populations in which efficient family-planning methods are widely used. Short-run variations in conventional period rates may result from variations in the number of women marrying at each age and in child-spacing patterns, rather than from the number of children born over the childbearing span. For example, marriage rates and the birth of a first child are rather closely correlated with the business cycle in highly industrialized countries (Kirk & Nortman 1959).

Fertility measures of historical cohorts. A major methodological advance in recent years is the measurement of the cumulative fertility of historical cohorts of women, taking into account the family-building sequence of marriage and the spacing of successive children (France … 1953). Ideally the data needed for each historical birth cohort include the percentage of each cohort dying, the percentage of the single marrying, the percentage with one previous birth having another, and so on. From annual empirical probabilities of this type, it is possible to reconstruct, to date, the cumulative fertility of a particular cohort or of the whole population. But only a few countries are beginning to collect these data.

In cohort analysis, the stages of family building are related to specific historical dates, not just to abstract age categories. It is therefore possible to link variations in family-building patterns for particular cohorts to time series for economic or other social phenomena.

Data for fertility studies . The newer, more sophisticated measures cannot be used in most countries at present, because they lack even the elementary data required for the simpler conventional measures. However, special efforts are being made to improve fertility statistics in some of the developing countries in order to measure the success of programs to reduce the birth rate [see POPULATION, article on POPULATION POLICIES].

Sample surveys are used increasingly to estimate fertility and other related phenomena, especially where other statistical resources are lacking. For example, a series of sample surveys is the principal basis for our knowledge of African populations. The sample survey is also often used to collect information about social factors that may affect fertility, since some of the most important intermediate variables, such as age at marriage or use of contraception, do not appear at all in the official series.

Fertility in preindustrial societies

Despite the lack of statistical data, it can be asserted with some confidence that fertility rates have been moderately high to very high in almost all preindustrial societies throughout history. With the high mortality levels that have prevailed in such societies, fertility had to be moderately high for the society to survive.

An increasing volume of data for contemporary preindustrial societies indicates, without exception, that fertility is at least moderately high (see Table 2). With the exception of the Tikopia, the

Table 2 — Distribution of less and more economically developed countries by level of crude birth rate, 1963

only substantiated instances of relatively low fertility in preindustrial societies are those subject to extreme social disorganization (Lorimer 1954, chapter 3). From the point of view of a preindustrial society, of course, high fertility is a functional adjustment to high mortality; but from the point of view of the reproducing couple, high fertility is motivated by the central importance of familial and kinship ties in their lives. Motivations for larger numbers of children are increased when children enhance the ability of the familial unit to attain socially valued goals, and when such goals are attained through kinship and familial ties rather than through other social relationships.

Fertility and social values . Although a reasonably large number of children may be vitally important to parents in a preindustrial society, this does not necessarily mean that the normative value is for the highest possible fertility. But evidence on the existing norm in preindustrial societies is less than satisfactory. Ford (1945) has indicated that the normative pressures against childlessness and against very small families are great and probably universal in preindustrial societies. However, he has also concluded that mothers are ambivalent about childbirth in many circumstances and that considerable social pressure may be required to ensure adequate reproduction. Davis and Blake (1956) have pointed out that since to have some children is very important, a society with high and variable mortality is likely to have built into its structure very strong pressures for bearing children early in marriage, before the death of one or both parents, and also to have additional children as a safeguard against the catastrophic loss of the essential minimum number. On the other hand, if unfavorable conditions develop, this may result in “too many” children. Therefore, there may be a delicate balance between pressures that tend toward higher fertility, to ensure at least a certain minimum number of children, and contrary pressures that encourage abortion or infanticide in order to minimize or eliminate what, under difficult subsistence conditions, becomes an intolerable surplus. In any case, although there is general agreement that fertility is likely to be high in almost all preindustrial societies, there is also a body of evidence about the existence of control practices that keep fertility below a potential biological maximum, and about cultural and social factors that produce variations in fertility through these practices.

Cultural effects on intermediate variables . On the question of control, there is evidence that the “natural fertility” of man is probably higher than that reported for most preindustrial societies (Lorimer 1954, chapter 1; Henry 1961), but genetic differentials in fecundity cannot be ruled out. Health conditions reducing fecundity and increasing fetal mortality may constitute a functional, if unintended, adjustment to keep fertility below maximum levels.

Evidence has been assembled on the use of a wide variety of control measures—including contraception, abstinence, abortion, and infanticide— in many preindustrial societies (Himes 1936; Devereux 1955; Nag 1962). Unfortunately, the evidence usually demonstrates the existence of certain practices in a culture without specifying either the extent of use or the effect on fertility. Nevertheless, there is a basis for the tentative generalization that more or less effective methods of control potentially were available in many preindustrial societies, probably affected fertility levels in some, and, presumably, might have had a much wider use and effect were it not for the rewards derived from having children in such societies and the risk that these rewards would be lost because of unpredictably high mortality [see FERTILITY CONTROL].

There are no empirically validated general explanations for the variations in fertility from high to very high among preindustrial societies. It is often possible to point to particular intermediate variables as the immediate causes of less than maximum fertility, but even in these instances the level of the intermediate variables is a topic that so far has given rise to explanations that are at best speculative.

Among the most important attempts at general explanation are those linking variations in kinship structure to variations in fertility (Lorimer 1954, chapter 2). A specific example of importance is the hypothesis that neolocal nuclear family systems and related economic arrangements led to late marriage or nonmarriage in preindustrial Europe, producing relatively low birth rates (Evers-ley 1963). If this is true, it runs counter to the most commonly held theories, which associate such birth rates with industrialization. It has also been suggested that some institutions may function to limit fertility, although this is not their deliberate purpose. For example, many religious systems prescribe periods of sexual abstinence, which usually (although not always) have the indirect effect of limiting fertility (Nag 1962).

Another unintended restraint on fertility is the possible reduction in fecundity resulting from poor nutrition and health conditions, whether these affect the whole society or only the lowest strata. This is one possible explanation for the fact that in some Indian studies the poorest rural workers have the lowest fertility. Another finding is that the period of amenorrhea and temporary sterility following a pregnancy apparently is lengthened if an infant lives and is breast-fed. This suggests that variations in infant mortality and in weaning practices may also affect fertility (Potter et al. 1966).

Lack of an adequate contraceptive technology has been suggested as an explanation for high fertility in preindustrial societies (Davis & Blake 1956, p. 223). An opposing point of view is that contraceptive practices are not developed or widely disseminated when available, because the structure of such a traditional society provides little motivation for small rather than large families. Coitus interruptus, probably the principal means for modern fertility decline in England and France, has been practiced for centuries by some couples within many preindustrial societies. If sufficient motivation for small families had been present, such a method might have been adopted more widely, in at least a few preindustrial societies.

These are only illustrations of theories and studies indicating that a variety of cultural factors in preindustrial societies affect the intermediate variables in such a way as to keep fertility below its maximum biological potential. Since many of the limits on fertility are based on cultural patterns without consciously recognized links to family size, changes in such practices initially may lead to higher fertility before modern family-planning practices take their place. For example, this might be the result of a further relaxation of traditional sanctions against the remarriage of widows in India.

Fertility in industrial countries

Transitional decline of fertility. The large decline in fertility in economically developed countries in the nineteenth and twentieth centuries is unprecedented. Most sociologists and demographers would probably agree that there have been two basic causes for the general decline. In the first place, there has been a major transfer of functions from the family to other specialized institutions, so that fewer children are required to achieve socially valued goals. Second, a sharp reduction in mortality has reduced the number of births necessary to have any desired number of living children.

The historical timing of fertility decline in most countries, rather long after the beginning of the modern process of economic development and social change, has been explained in terms of a descriptive model of the “demographic transition.” This model assumes that fertility and mortality are both high in the preindustrial period. The rapid population growth associated with modern economic development is then attributed to a decline in mortality that occurred while fertility remained relatively stable at rather high levels. It is further assumed that after a considerable time lag, fertility begins to fall, reducing the rate of population growth as it approaches the level of mortality. The usual explanation of this time lag is that whereas low mortality is always positively valued, there are no low fertility norms to carry over from the preindustrial period; they must be developed gradually in a trial-and-error process, under the influence of lower mortality and the changing consequences of varying numbers of children.

This simple model of the demographic transition is under revision as the result of a number of important studies. Some have shown a considerable variability in the actual course of the demographic transition (Halt et al. 1955; Ryder 1957). Especially significant has been the work of a number of economic historians (for instance, Eversley 1963) probing, in detail, European data for the medieval period and for the seventeenth and eighteenth centuries. These studies have tried to relate changes in economic organization and in family structure to changes in age at marriage, rate of marriage, and illegitimacy. An important, if controversial, hypothesis emerging from this work is that a rise in fertility rather than a fall in mortality may be responsible for the population growth during the early stages of industrialization.

Explanations for the decline in fertility that eventually occurred throughout the Western world sometimes concentrate on the intermediate variables and sometimes on the changes in social structure, which first produced the small family norms and then affected the intermediate variables.

The role of contraception. Most scholars probably would agree that the mass adoption of contraception is the most important change immediately responsible for the decline in fertility in modern industrial countries. Notable exceptions are Ireland, where men have tended to marry late or not at all, and Japan and the countries of eastern and central Europe, where abortion has been widely practiced since World War II.

It has generally been assumed that contraception was the most important factor in the development of the small family that gradually became the norm for western Europe. But this assumption must remain, at best, a plausible hypothesis, since there is an almost complete lack of systematic comparative data for many of the other intermediate variables affecting fertility. The only study providing a series of historical statistics on the use of contraception is that by Lewis-Faning for England (Great Britain … 1949). He demonstrated that as the use of contraception increased, fertility declined, and that contraception was adopted first in those social classes whose fertility fell first. The practice was found to have spread to other social classes in reasonably close correspondence to observed patterns of differential fertility. There is also illustrative evidence about the adoption of contraception—especially coitus interruptus—by significant elements in the French population in the late eighteenth and early nineteenth centuries; and it so happens that this was the period in which fertility in France began to fall (France … 1960).

Since the war several studies have provided statistical evidence of the mass use of contraception in a number of Western countries and have related the practice to fertility levels (e.g., Freedman 1961, pp. 116-118). These studies do indeed demonstrate that many populations with a history of marked secular decline in fertility now practice family planning on a massive scale; but another finding that they also have in common is that contraceptive practice is not necessarily highly rational and effective, even when the average number of children per family is limited to two or three. Even in the United States, where contraception is virtually universal for the fecund at some time in married life, many couples use ineffective means, many do not begin contraception early in marriage (although they do not want all their children immediately), some begin only after having more children than they want, and many conceive despite contraceptive efforts to postpone pregnancies (Freedman et al. 1959, chapters 3-6). In Japan and a number of east European countries, the failure of contraception as practiced to produce the small families desired has been followed by massive supplementary use of legal abortion.

Biological theories. Before World War II, it was not uncommon to attribute the decline in fertility to a decrease in biological fecundity. The main argument was that development of industrial-urban society brought about a decrease in fecundity. This was held to be a consequence either of genetic selection or of the stresses supposedly associated with urban life—especially for the higher status groups, whose fertility fell fastest. Although such explanations may be valid for special situations, the prevailing scholarly opinion does not assign it great importance in the over-all fertility decline in Western countries. Kiser and Whelpton, in the Indianapolis study, demonstrated both that a modern urban population can have a high fertility rate during periods when contraception is not used and that fecundity differences are not associated with socioeconomic status in the way that they should be if the biological argument about fecundity decline is true (see Whelpton 1943-1958, vol. 2, pp. 303-416). This argument has also been weakened by the difficulty of reconciling it with the temporal changes in fertility that have been observed to follow changes in economic conditions.

Whatever combination of intermediate variables was responsible, there is no question that fertility fell rapidly in all the developed Western countries, so that just before World War II small families averaging closer to two than three children were characteristic. In many countries, fertility was below the level required for replacement even with the very low prevalent mortality, and concern about a declining and aging population led to national investigations and official pronatalist policies.

Sociological theories. Many explanations were advanced for these unprecedented fertility declines. The dominant ideas before World War II, however, were all related to the changing functions of family and children in an urban-industrial society. To summarize the theories: Industrial urbanization was associated with a complex division of labor in all spheres of life; with the associated high rate of social and physical mobility, this inevitably led to a growth of secularism and rationalism, the declining influence of such traditional forces as religious faith, and the shattering of traditional family and other primary group associations. An essential element in this view of urban life was the idea that the family would lose its functions to other specialized institutions. On the one hand, children would cease to be productive assets in a familially based economy, and, on the other hand, they would be impediments to active participation in the larger organizations from which the rewards of an urban society would come. The dominant view was that as whole populations became involved in the urban market and society, family planning would become universal and the size of family planned would continue to decline.

It is plausible that a shift in functions from the family to other institutions is one basic explanation for the secular decline in fertility in the developed countries. But in retrospect there is little systematic evidence in prewar studies linking specific changes in the functions of the family to the decline of fertility at specific times and places. There are still no satisfactory answers to some important comparative historical questions, for example: Why did fertility begin to decline much earlier in France than in England, where urban-industrial development was earlier and more intense? Why has fertility remained higher in the Netherlands than elsewhere, despite that country’s early involvement in the nexus of international trade?

One line of theory and research has stressed the joint role of social mobility and rising standards of living in motivating couples to restrict family size. This is one explanation offered for the early decline of fertility in France (Blacker 1957). Banks (1954) has linked the onset of the fertility decline in England with a change in economic conditions that made restriction of family size necessary for the maintenance and advance of living standards in the rising middle class. More recent statistical studies produce conflicting results, with some indicating no correlation between mobility and fertility in the United States (Westoff et al. 1961) and others finding a relationship in France (Bresard 1950), England (Berent 1952), and Brazil (Hutchinson 1961). Even in those cases in which a relationship is found, it is possible that the distinctive fertility of the mobile population is simply an averaging of the fertility levels of their positions of origin and destination, and not a distinctive consequence of social mobility itself.

Postwar fertility increase in the West . A decrease in childlessness is only one of the important postwar demographic trends that direct attention to the need for a re-evaluation of the role of family and children in society. In most of the developed countries in which fertility reached very low levels before the war, there has been an increase in the proportion of people marrying, a decrease in the age at marriage, and an increase or stabilization in the average family size of those who marry. There is, however, little evidence of a return to large families since the war; the shift is from having no children or one child to having from two to four. In a number of countries, an increase in the number of marriages, rather than in the number of children per marriage, accounts for a significant part of the postwar rise in fertility.

Since the war, urban sociologists have given increasing recognition to the persistence and even the resurgence of primary groups, including the family, as the means by which stable individual personality organization is maintained in impersonal specialized societies. Part of this revaluation of urban society involves more attention to the persistent influence of traditional ideologies in religious and other associations with ends that are not primarily economic or political. Such associations had been doomed to extinction by prewar sociologists, who were fond of stressing the growth of secular rationalism. By contrast, a community study by Lenski (1961) shows the persistence of Catholic ideology in many areas of life, including fertility, even after the consideration of the influence of rising education, socioeconomic status, and urbanization. These results are confirmed, with more demographic detail for fertility, in the Princeton study (Westoff et al. 1961).

Some sociologists and demographers have suggested that the leveling off in the long-run secular decline in fertility may mean that family size has reached a level appropriate to its functions under urban-industrial conditions. From this viewpoint, considerable experimentation may be required before a stable social norm is developed governing the size of such an important unit as the family. The very low fertility of the 1930s is seen as an experimental “overshooting” of an “equilibrium solution,” with a readjustment following when the dysfunctional consequences were widely felt. The increasing convergence of family size in many countries to a small range of one to four children may be additional evidence that a family-size pattern appropriate to urban-industrial societies is developing (Universities-National Bureau Committee for Economic Research 1960, pp. 36-76).

Differential fertility

Differential fertility refers to variation in fertility among significant subgroups in a population. In principle, almost any classification of the population may be a basis for measuring fertility differences. Scholarly attention, however, has centered on groups of people whose differing positions in the society give them different resources, styles of life, and power. Such groups frequently are distinctive in social norms and culture traits affecting fertility.

General principles . Classifications used in studies of differential fertility include those based on education, occupation, income, wealth, landholding, caste, social class, labor-force status of the wife, religion, ethnic-racial groupings, regional divisions, bureaucratic positions, intelligence, and size of place of residence. Occupation and education have been the most frequently used bases for classification, both because they are readily available in censuses and in official vital statistics and because they are significant indicators of status and style of life in most modern societies.

Social groups or strata that differ in their fertility differ also on one or more of the intermediate variables affecting fertility. Differentials may result from deliberate controls, such as contraception, or from the unintended consequences of other variations. For example, in some places, the rate of spontaneous abortions is higher in lower-status than in higher-status groups, and this has an unintended effect on the status differentials.

For a number of contemporary societies, there is evidence that the low-fertility subgroups have used deliberate family-limitation practices—mainly contraception and abortion—more extensively and effectively than other groups. Substantiating data are available, for example, for the United States, England, Japan, Hungary, Czechoslovakia, Puerto Rico, Turkey, India, and Taiwan.

It is more difficult to establish unequivocally whether the higher fertility subgroups have larger families because they want them or because they do not have the knowledge or means to restrict family size. Low motivation toward a small-family goal may reduce interest in learning and practicing effective family-planning methods. In the United States, there is evidence that the practice of contraception for spacing births becomes more effective as the number of children born to a couple approaches the desired total. This suggests that ineffective family planning may reflect a desire for more children rather than inability to use the proper means. On the other hand, the important Indianapolis study by Kiser and Whelpton in 1940 found that low-status and high-status groups expressed similar attitudes about desired family size but that the low-status groups had more children because they practiced contraception less effectively (Whelpton 1943-1958).

At least in societies in which socially significant groups of people deliberately practice family limitation, differential fertility levels will be affected by distinctive subgroup attitudes about how many children a family should have. Presumably, fertility will be higher and family limitation practices less prevalent or effective in subgroups in which larger numbers of children are rewarding in various ways. The relatively high fertility of the agricultural sector of many populations, for example, can be linked to the utility of children, whether as laborers in the family enterprise, as an alternative to urban social-security programs to meet the risks of illness, disability, and old-age, or as the members of essential primary social groups. Similar functions have been ascribed to larger numbers of children among low-status urban groups during the period of transition to a modern economy.

Fertility differentials often do not correspond to the differentials in the rate of reproduction—a measure that also takes mortality into account. For example, in countries as different as India and England, the mortality rate is considerably higher in lower-status than in higher-status groups. Therefore, by the time a given cohort of women has reached the end of the childbearing period, differences between social strata in the number of living children per mother often vary considerably from differences in the average number of children ever born to each mother.

Fertility differentials by status measures . Such stratification measures as education, occupation, or income have been studied most extensively in relation to fertility, partly because data are available in standard demographic sources, but also because stratification is important in social and economic theory (United Nations … 1953, chapter 5). Socially patterned differences in life style and economic activity presumably may influence either the social norms about family size or the variables immediately determining fertility, such as fetal mortality and effective access to contraception. But there is no single, universally valid relation between status measures and fertility, because such particular indications of status as education or land-ownership vary in their significance in different societies and because the value attached to large families is greater in some societies than in others. Indeed, the resources that go with high status are likely to be used to achieve large families in some societies and small families in others.

For preindustrial societies, there is evidence in some studies of a positive correlation between fertility and status, especially among agricultural populations (Stys 1957). The nature of the evidence varies. Fertility has been found to increase with size of landholding; agricultural tenants or workers have been found to have lower fertility than landholders; persons with low-status occupations have been reported to have lower-than-average fertility. The evidence for a positive correlation is reported in regional studies for England, Germany, Poland, China, the United States, India, and the Philippines for various periods between the seventeenth and twentieth centuries.

A plausible explanation of positive correlations between fertility and status in preindustrial societies is that dependence on relatives and children for a variety of social needs increases the social valuation of large families, so that those with higher status use their power to increase family size (for example, by early marriage). It is also plausible that in some instances poor health, poor nutrition, the absence of males seeking work, or high maternal mortality among fertile lower-status mothers may explain the lower fertility for lower-status groups. The thesis that higher fertility invariably goes with higher status in all preindustrial societies is certainly not supported by the evidence. For example, in some contemporary regional studies of peasant populations in India, there is no correlation between status measures and fertility (Chandrasekaran 1963).

A negative correlation between occupational status and fertility in Western urban populations appears with the earliest pertinent census data in the nineteenth century (United Nations 1953). In the period of transition to a mature industrial-urban society, negative correlations between broad status measures and fertility are found wherever systematic data are available. Although the evidence is mainly for Western countries, similar negative relationships have been reported for the advanced changing urban sectors in such diverse places as India, Taiwan, Chile, Puerto Rico, and Lebanon. Plausible explanations for these negative correlations center on the idea that high-status groups live first in the developing urban-industrial sectors in which they enjoy a number of advantages. These would include superior access to information about the means for fertility control, later marriage because of higher educational standards, and lower mortality rates (making fewer births necessary for any desired number of children). Such families, it is argued, would find the economic value of children relatively small in the course of acquiring higher living standards for themselves and their children. They would also be likely to participate in extrafamilial activities, which could occupy time that might otherwise have been given to additional children. Whatever the explanation, the existence of the negative relation between status and fertility is well documented for many places.

The lower fertility of high-status groups in the period of transition to advanced industrialization may be the result of both the smaller proportion marrying at important child-bearing ages and the use of contraception to limit family size within marriage. Historical data for status differentials in the use of contraception corresponding to differentials in fertility are available only for England, as already mentioned (Great Britain … 1949). However, similar differentials in use of contraception have appeared later in other countries, as data become available. More recently, there is evidence that the differential use of legal abortion is producing fertility status differentials in Japan and in some countries of eastern Europe.

At least in the United States, the higher fertility of low-status groups is partly a consequence of their rural origin rather than of their status in the urban community (Goldberg 1959). There is a high proportion of farm-reared persons in low-status groups, whether these are defined in terms of occupation, income, or education. When only couples living in cities for at least two generations are considered, either the status differentials become slightly positive or the negative correlation is reduced. This is consistent with the thesis that the negative correlation is part of the transition to a mature urban society rather than an intrinsic characteristic of such a society.

The negative relation of status to fertility is most pronounced in data for the period before World War II. However, even at that time there were many exceptions within broad occupational groups. For example, low fertility is reported among service workers, such as barbers and waiters, having frequent contact with higher-status groups. For the period between the world wars, the highest income groups sometimes had higher fertility rates than the next income group, especially when comparisons are made for persons of high educational or occupational status.

There was a sharp contraction in fertility differentials in many countries in the “baby boom” following World War II. Fertility generally increased most in those social strata which had the lowest fertility before the war. However, even in the United States, where this phenomenon was very pronounced, there continued to be significant negative correlations between various status measures and fertility (Grabill et al. 1958).

Postwar studies, mainly in the United States, indicate that there is now very little relationship between measures of social status and the number of children desired and expected. It is not yet known whether the expectations and desires of each stratum will be realized in action. Apart from possible changes in what is desired, the present evidence is that lower-status groups still are less effective in planning their fertility to attain desired family size.

Some scholars believe that in a mature urban-industrial society fertility eventually will be positively correlated with status—and especially with income (Universities-National Bureau … 1960, pp. 209-240). A basic assumption is that effective use of contraception, together with very low mortality rates, will diffuse throughout the society, so that the fertility of each stratum will directly reflect the value of varying numbers of children in that stratum. Children, it is argued, having lost their differential utility as laborers or as social security resources, will be valued by all social classes for direct satisfactions, such as those yielded by durable consumer goods. The higher-income groups will then be able to afford and will choose to have more children than low-income groups. There is some support for this argument in data showing that there is a small positive correlation of income and fertility among couples who plan family size effectively and that this correlation is highest for couples with an urban background (Whelpton 1943-1958, vol. 3, pp. 360-415).

This projection of a positive correlation in the mature urban society makes assumptions, still unverified, about the elasticity of demand for children. One could just as well argue that the higher educational status generally found with higher income may lead to a broadening of interests, which will compete for attention with the demands of larger families. The theory also assumes that in the modern welfare state even the lowest status groups can receive from nonfamilial institutions assistance formerly received from children in meeting the risks of illness, disability, unemployment, old age, and loneliness.

Differentials by city size and farm residence . In industrialized countries, fertility is almost always highest in the farm sector and tends to decrease as the size of the community increases. The explanation generally offered is twofold: it is said that contraception diffused from larger to smaller cities, and from there to the farms, and that the functional advantages of larger families are greatest, and their costs least, in smaller communities and on farms.

With the postwar rise in birth rates, fertility differentials by city size probably decreased in many countries, since fertility increased most in the status groups concentrated in large cities. Nevertheless, the traditional differentials persist in most Western countries for which there are adequate data. It is not yet clear whether the remaining inverse relation of fertility to city size in developed countries is a permanent feature of their structure, or a transitional phenomenon.

In the United States, at any rate, urban-rural fertility differentials have existed from a very early time. Declines in fertility in the rural and urban sectors followed parallel courses until about 1940, but since then urban fertility rates have risen more than the rural rates, thus reducing the differential. In a number of preindustrial countries (India, for example) urban-rural fertility differentials either do not exist or are minimal (Robinson 1961). In such societies, cities are often administrative and political centers in which familial organization does not differ greatly from that in rural areas; the city lacks the specialized institutions that take over many family functions in industrial societies.

Religious differentials . Most research on religious fertility differentials deals with the specific influence of the Roman Catholic church in limiting the practice of family planning (except by periodic abstinence) and in supporting norms for larger families. The doctrines of the church do not require large families, but they do restrict the means that may be used to achieve smaller families. The fact that empirical findings differ with the country studied suggests that the influence of the church depends on other variables in the society. In the United States, close attachment to the church is associated with higher fertility and with lesser use of the most effective fertility-control practices, even among higher-status groups. Lenski (1961) explains this result by an emphasis in Catholicism on familial rather than economic mobility values. But studies in Puerto Rico and other Latin American areas find no relation between attachment to the church and fertility. Indeed, international comparisons of fertility do not show any significant correlation between fertility and the percentage of Catholics in the population, when the level of general social development is taken into account.

Most of the other major world religions do not have specific doctrines about family limitation. However, religious practices frequently have an indirect effect on fertility. For example, in both India and China major religious traditions support a strong preference for at least one and preferably two sons, thus increasing the pressures for additional children. A pervasive fatalism in a religious ideology may have a greater effect than a specific injunction against contraception in impeding rational planning of fertility.

Other differentials . In industrial societies, wives who work away from home are found to have fewer children than those who stay at home. Some women work because they cannot have children, but the lower fertility of working women persists even when only fecund women are considered. Where the wife’s work is closely tied to the home, lower fertility may not result. In Japan and Puerto Rico, women who worked at home or in small family enterprises were found to have higher fertility than other working wives.

Fertility differentials between ethnic, racial, or regional populations are extensively studied, because of their practical economic or political significance. But the meaning of the differentials depends on their specific historical and cultural context. Sometimes it is possible to explain such differentials in terms of status or rural-urban differences; otherwise, no successful analytic generalization of these studies has been made.

Consequences of differential fertility . Much of the early interest in differential fertility was eugenic. It was feared that the genetic quality of the population would deteriorate if low-status groups had higher-than-average fertility. This assumes that lower-status groups are more poorly endowed genetically—for example, with respect to intelligence —but this has not been scientifically established. Certain types of mental abnormality have a known genetic basis, but they are not sufficiently numerous to affect broad status differentials. It is likely that high or low fecundity itself may have a genetic basis, but this also is not known to have any specific connection to broad socially significant strata. Whether there are important genetic differences between social strata is still an open question. Probably, there is greater consensus that differential fertility may produce a social problem, regardless of the genetic origin of the problem, if fertility is high in groups with limited personal or social resources for child-rearing. There is some evidence that intellectual development is greater for children reared in small families; but the apparent contraction of fertility differentials in the postwar period in industrial countries has reduced the earlier concern about the social and biological consequences of differential fertility.

Differential fertility may affect the rate and character of social mobility. Varying rates of reproduction of different social strata affect the relative number of opportunities available in each stratum, depending on the extent of social inheritance of position. More generally, the rate of recruitment of new members is one important determinant of the continuity, structure, and power of any subgroup in the population. Recruitment from other groups by adoption or invasion is an alternative to reproduction, but differential fertility is often the principal determinant of the relative growth of population subgroups from generation to generation. Where success of groups contesting for political power depends on their size, a lively concern about comparative reproduction rates often is evident.

Ronald Freedman

[Directly related are the entriesGENETICS, article onDEMOGRAPHY AND POPULATION GENETICS; POPULATION. Other relevant material may be found inMIGRATION; MORTALITY; NUPTIALITY.]

BIBLIOGRAPHY

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Devereux, George 1955 A Study of Abortion in Primitive Societies: A Typological, Distributional, and Dynamic Analysis of the Prevention of Birth in 400 Preindustrial Societies. New York: Julian.

Duncan, Otis Dudley 1965 Farm Background and Differential Fertility. Demography 2: 240–249.

EVERSLEY, D. E. C. 1963 Population in England in the Eighteenth Century: An Appraisal of Current Research. Volume 1, pages 573-582 in International Population Conference, New York, 1961, Proceedings. London: International Union for the Scientific Study of Population.

Ford, Clellan S. 1945 A Comparative Study of Human Reproduction. Yale University Publications in Anthropology, No. 32. New Haven: Yale Univ. Press.

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Grabill, Wilson H.; RISER, C. V.; and WHELPTON, P. K. 1958 The Fertility of American Women. Prepared for the Social Science Research Council in cooperation with the U.S. Department of Commerce, Bureau of the Census. New York: Wiley.

GREAT BRITAIN, ROYAL COMMISSION ON POPULATION 1949 Papers. Volume 1: Family Limitation and Its Influence on Human Fertility During the Past Fifty Years, by E. Lewis-Faning. London: H.M. Stationery Office.

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KIRK, DUDLEY; and NORTMAN, DOROTHY L. 1959 Business and Babies: The Influence of the Business Cycle on Birth Rates. Pages 151-160 in American Statistical Association, Social Statistics Section, Proceedings. Washington: The Association.

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Robinson, Warhen C. 1961 Urban-Rural Differences in Indian Fertility. Population Studies14 : 218–234.

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Fertility

The conceptions of human life and death are processes full of symbolic and cultural meanings. How the social meaning of human reproduction is constructed depends on the given sociopolitical context. Although the planet as a whole tries to cope with the consequences of overpopulation, in many developed countries governments are worried about the falling birth rates. When studying reproduction and the microprocess of conception, it is important to account for how local and global political tendencies affect population and individual reproductive health (Inhorn and Whittle 2001).

Reproductive health is affected by genetic endowment and by the physical and social environment. Thus it can be improved or undermined by individual behavior, advanced by better socioeconomic living conditions, and changed with medical knowledge and services (Pollard 1994). For example, nutrition during pregnancy affects the health of the fetus and may affect its subsequent viability. Living conditions and access to health care during childhood affects individuals both as children and adults. Education and later work possibilities affect not only individuals' overall life resources and health but also their reproductive health life style and health habits (Davey Smith et al. 2000). Excessive cigarette smoking, alcohol consumption, caffeine intake, obesity—as well as extreme weight loss and physical exercise—have been shown to adversely affect fertility (Feichtinger 1991).

Conception

Conception as a biological matter and a part of human reproduction means fertilization in which a sperm makes contact with an egg, fuses with it, and develops into the zygote, embryo, and fetus (Birke, Himmelweit, and Vines 1990). The monthly probability of conception without contraception is called fecundability, which for fertile couples is approximately 25 to 30 percent per month (Spira 1986), a remarkably low figure. Nevertheless, among humans fertilization can occur any given month, whereas among many other species fecundity is usually limited only to certain time of the year. An individual woman's fecundity varies as a function of her age, menstrual cycle, ovulation, and the functional status of her genital organs. Women in their 20s usually show the highest fecundability, which decreases among those over 35 years old (Day Baird and Strassmann 2000). Both female oocyte, or female egg, and uterine quality worsen with age, as do a woman's capacity to become pregnant and deliver a healthy child. In the era of birth control methods, for example, women in the United States and Finland reproduce relatively rarely, because only about 6 percent of them (15–44 years of age) give birth annually. A man's fecundity correspondingly varies with his age and seasonal and environmental factors. There is ample proof that environmental pollutants and occupational exposures to hazardous substances, such as radiation, heat, solvents, and pesticides, have adverse effects on male fertility (Feichtinger 1991). Fewer studies have inquired into the environmental effect on female fertility (Baranski 1993).

Reproductive System

In general, reproduction concerns women more profoundly than men in the physiological and social senses, because conception and development of a fetus happen in woman's body: she gives birth to the child, usually cares for it, and motherhood is culturally more important social and personal identity and institution than fatherhood. However, a woman and a man are both needed for conception (or at least female and male gametes—female egg and male sperm—are needed in assisted reproduction). A couple that has achieved a pregnancy is considered fertile. A woman and man must be sufficiently healthy to conceive. A healthy, fertile woman has approximately 400,000 immature eggs in her ovaries at the time of her birth. From puberty until menopause a woman's body goes through ovulation, in other words, periodic cycles of physical and chemical change during which an egg matures and is released from an ovary into one of the two fallopian tubes (Royal Commission on New Reproductive Technologies 1993). A woman must have at least one functional ovary and her tubes must be open and function to transport the egg to the uterus. The probability of conceiving a surviving pregnancy is highest on the two days before ovulation.

A healthy, fertile man produces 2.4–5 milliliters of semen containing between 200 million and 500 million sperm at each ejaculation. In order to conceive the anatomies of the man and woman have to be normal and their physiological and hormonal systems must function normally at the right time. The hypothalamus at the base of the brain orchestrates the body's hormonal reproductive function. Next, natural conception requires timely oocyte release, sexual intercourse, and the transport of gametes through the female reproductive tract. The woman's hormone level must be sufficient to stimulate the production of eggs and normal cervical mucus. Proper cervical mucus is necessary both near the time of ovulation and later to support implantation of the embryo and maintain pregnancy. Correspondingly, a man must be able to produce an adequate number of normal sperm and must be able to deposit them in the woman's vagina at the appropriate time during the female ovulation cycle (Office of Technology Assessment 1988). Only one sperm is needed to join with an egg in a woman's uterus for fertilization to occur. For this to happen, however, the sperm must be physically and functionally normal, active, and capable of swimming through the woman's reproductive tract.

Infertility

The production and the delivery of eggs and sperm are vulnerable processes that anatomical, genetic, hormonal, behavioral, and environmental problems may interrupt and prevent. Infertility is defined in clinical practice as the inability to become pregnant after more than one year of unprotected inter-course. Infertility can be either primary, if the couple has never achieved a pregnancy, or secondary, if it occurs after a couple has already had one or more pregnancy. Worldwide some form of infertility may affect 8 to 12 percent of couples (Day Baird and Strassman 2000; Spira 1986). Infertility is rarely absolute in nature, whereas sterility means the complete, absolute absence of reproductive capacity (the incidence has been estimated to be 3–5% of couples in industrialized countries [Spira 1986]). Female fertility problems may result from disorders in oocyte production, blockage or adhesions of the fallopian tubes, endometriosis (presence of endometrial gland tissue outside the uterus), or uterine and cervical abnormalities. Male infertility may be due to the problems in spermatogenesis (formation of sperm) and sperm transport and maturation (see Goldman, Missmer, and Barbieri 2000).

In Western countries the majority of women are accustomed to controlling their fertility with effective, accessible, and safe birth control methods and abortion. Likewise, Western women with fertility problems are accustomed to seeking medical help in order to become pregnant (Scritchfield 1989). Not every sterile and infertile couple wishes to have children. Thus, a woman and her partner must desire to have children but be physiologically incapable of becoming pregnant to experience herself as infertile and seek medical help.

Medical Procedures to Increase Fertility

There are medical procedures which may increase a person's fertility. Although sexually transmitted diseases (STDs, such as gonorrhea, syphilis, and chlamydia) and, for women, pelvic inflammatory diseases (PID), are predominant causes of infertility, preventive actions can decrease the possibility of contracting an STD or PID or suffering adverse environmental and/or occupational effects. Curative procedures include gynecological and urological surgery (e.g., surgery to open blocked fallopian tubes in women, or correct varicose veins in men). There are also infertility-bypassing procedures, which are called assisted reproductive technologies (ARTs), because they do not cure the physiological cause of the infertility. These ARTs include low-tech therapies, such as hormone medications and intrauterine insemination using sperm from the woman's partner or from a donor. High-tech procedures, which include retrieval of oocytes or fertilization of gametes outside the female body, are referred to as in-vitro fertilization (IVF) and related technologies. In IVF, eggs are fertilized outside the female body, and the embryo(s) are cultured in the laboratory; later, fresh or frozen embryo(s) are transferred to the female uterus (Grainger and Tjaden 2000). In IVF, donated gametes and embryos can also be used. When combined with surrogate motherhood, IVF can be used for couples in which the woman is without a womb. Other IVF-related technologies are zygote intrafallopian transfer (ZIFT), in which embryos are transferred to the fallopian tubes, and gamete intrafallopian transfer (GIFT), in which the egg and sperm are placed in a woman's fallopian tubes (Fidler and Bernstein 1999). The most common micromanipulation technique is intracytoplasmic sperm injection (ICSI) where one sperm is inserted into an egg in the laboratory. The access to these high-tech ART procedures depends on the local health care system and insurance coverage. Overall, about half amillion children worldwide have been conceived with the help of IVF; and in the United States it has been estimated that approximately 29,000 IVF children are born annually; in Europe, approximately 40,000 IVF children are born annually (Nygren, Andersen, and the EIM 2001; Use of Assisted Reproductive Technology 1999)

IVF has revolutionized reproduction: IVF can be used to treat fertile couples for concerns unrelated to infertility; IVF may be used for embryo biopsy for purposes of sex selection and genetic diagnosis; IVF may be used to store gametes of cancer patients before starting chemotherapy (Lass, Akagbosu, and Brinsden 2001). Insemination can to be used for single women or lesbian couples (Baetens and Brewaeys 2001). IVF with donated eggs is used for postmenopausal women (Sauer, Paulson, and Lobo 1993). Surrogate motherhood, combined with IVF, can be used for homosexual male couples. Thus, the ARTs have widened the human possibilities to reproduce.

Conclusion

The social meanings of reproduction phenomena are constructed differently depending on the given sociopolitical context. Local and global political tendencies as well as different social hierarchies have an impact on the reproductive health of populations and individuals (Inhorn and Whittle 2001). Gender, race, and nation mediate individuals' power, personal agency, and choices relating to their reproductive health (Krieger et al. 1993). Genetic endowment and the physical and social environments (for example, environmental pollutants and occupational exposures) also affect the reproductive health of both women and men. There are various medical procedures that may increase a person's fertility and enable the birth of a wanted child. But emotionally and economically the best solution for infertility is the prevention of infertility at different levels of everyday life.

See also:Abortion; Assisted Reproductive Technologies; Birth Control: Contraceptive Methods; Birth Control: Sociocultural and Historical Aspects; Childlessness; Family Planning; Fatherhood; Industrialization; Menarche; Menopause; Motherhood; Pregnancy and Birth; Sexuality in Adulthood; Surrogacy

Bibliography

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birke, l.; himmelweit, s.; and vines, g. (1990). tomorrow's child: reproductive technologies in the 90s. london: virago press.

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fidler, a. t., and bernstein, j. (1999). "infertility: from apersonal to a public health problem." public health reports 114:495–511.

davey smith, g.; chasturvedi, n.; harding, s.; nazroo, j.; and williams, r. (2000). "ethnic inequalities in health: a review of uk epidemiological evidence." critical public health 10:375–408.

day baird, d., and strassmann, b. i. (2000). "women's fecundability and factors affecting it." in women and health, ed. m. b. goldman and m. c. hatch. san diego, ca: academic press.

goldman, m. b.; missmer, s. a.; and barbieri, r. l. (2000)."infertility." in women and health, ed. m. b. goldman and m. c. hatch. san diego, ca: academic press.

grainger, d. a., and tjaden, b. l. (2000). "assisted reproductive technologies." in women and health, ed.m. b. goldman and m. c. hatch. san diego, ca: academic press.

inhorn, m. c., and whittle, k. l. (2001). "feminism meets the 'new' epidemiologies: toward an appraisal of antifeminist biases in epidemiological research on women's health." social science and medicine 53: 553–567

krieger, n.; rowley, d. l.; herman, a. a.; avery, b.;phillips, m. t. (1993). "racism, sexism, and social class: implications for studies of health, disease, and well-being." american journal of preventive medicine 9:82–122.

lass, a.; akagbosu, f.; and brinsden, p. (2001). "spermbanking and assisted reproduction treatment for couples following cancer treatment of the male partner." human reproduction update 7:370–377.

nygren, k.g.; andersen, a. n.; and the european ivf-monitoring programme (eim). (2001). "assisted reproductive technology in europe, 1998. results generated from european registers by eshre. european society of human reproduction and embryology." human reproduction 16:2459–2471.

office of technology assessment. (1988). infertility: medical and social choices. ota-ba-358. washington, dc: government printing office.

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pollard, i. (1994) a guide to reproduction: social issues and human concerns. cambridge, uk: cambridge university press.

sauer, m. v.; paulson, r. j.; and lobo, r. a. (1993). "pregnancy after age 50: application of oocyte donation to women after natural menopause." lancet 341: 321–323.

scritchfield, s. a. (1989). "the social construction of infertility: from private matter to social concern." in images and issues: typifying contemporary social problems, ed. j. best. new york: aldine de gruyter.

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maili malin

fertility The French word ‘fertilité’ entered the English language in 1490 to characterize the richness of the soil. By the seventeenth century, writers adapted ‘fertility’ to describe creative imaginations. In the course of the nineteenth century, the term ‘fertility’ came to account for the number of children a woman bore. In this period, too, fertility and another French term, ‘fécundité’, were used to refer to female procreative abilities. In 1866 J. M. Duncan differentiated fecundity from fertility with this explanation: ‘… by fecundity I mean the demonstrated capability to bear children … fertility implies fecundity, and also introduces the idea of number of progeny’ (The Oxford English Dictionary, 1989, 2nd edn). After 1866, especially among demographers, fertility increasingly came to refer to the number of live children a woman delivered.

Technically, fertility simply denotes successful production of offspring. This requires the development in the potential parents of mature eggs (ova) and sperm, sexual intercourse, the opportune encounter between sperm and egg in the woman's body, fertilization, implantation of the embryo in the uterus, successful antenatal development, and a safe birth. In the human female, the opportunity for fertilization lasts only a day or two following ovulation (the release of an ovum), which occurs about every 28 days, in the middle of the menstrual cycle. Sperm are present in vast numbers in the semen, so that, despite many hazards along the way, some survive the necessary journey to the egg. Given the typical frequency of coitus between habitual partners of reproductive age, the odds are in favour of pregnancy occurring within a few months of the first encounter, in the absence of contraception or any specific physical cause for infertility.

Fertility, however, is not simply the expression of a woman's bodily capacity to procreate (fecundity). Recent anthropological and feminist theory advocates understanding fertility as the product of individual actions situated within a particular historical and cultural context. Women and men, responding to local and global changes in the political economy and available resources (e.g. social networks, abortifacients, and contraceptives), act as individuals to produce the family arrangement they prefer (Greenhalgh 1995).

Women and men promote or control their fertility to meet particular needs and concerns at different moments in their life cycle, and these needs and concerns alter depending upon their sexual partner and the changing circumstances of their lives. A woman might attempt, for example, to limit her fertility with an extramarital partner, but not her spouse. Or a widow might attempt to control her fertility after her husband's death in her attempt to retain a particular social standing in her community or limit the economic strains on her household.

People negotiate the circumstances of their fertility differently according to their social position and their personal needs, interests, and concerns. In many societies, bearing a child grants a woman adult status in her community, provides her with a legitimate place in the adult community, and garners her political power in her household and sometimes in her community. The desire to have a child has led many women who wish to conceive to seek the assistance of herbalists, ritual experts, and clinics. The efficacy of fertility treatments depends not only on the male and female partners' reproductive capacities, but also on their financial ability to pay for the treatment and the quality of the drug or procedure. Places where women and men can have their fecundity tested and treated abound throughout the world.

The desire to limit fertility exists in concert with the wish to procreate, and many women experience both desires in their lifetimes. Women in countries around the world seek contraceptives and abortions to limit their fertility, with or without the consent of their partners. A recent study by Bledsoe and colleagues in West Africa, for example, found that some women who have just had a miscarriage elect to use contraceptives for a period to give their bodies a chance to recuperate before they choose to become pregnant again.

Beyond individual preferences, however, fertility responds to a number of factors. Chief among them are health, nutrition and environmental factors. A woman's nutritional status, age, and experience of disease contribute to the probability of subfecundity (reduced capacity to conceive), miscarriages, and stillbirths. The tragedy experienced by residents of the Love Canal, New York State, where unsuspecting families lived on toxic waste dumps, provides an example of how environmental hazards have increased the incidence of miscarriage.

Cultural and religious values relating to the onset and duration of sexual relationships, use of contraceptives, and frequency of coitus (with a fecund male), determine a woman's exposure to the possibility of pregnancy. Obviously, women who begin their reproductive careers immediately after the onset of puberty have a greater window of opportunity to experience pregnancy than women who delay childbearing. Additionally, women in societies that condone the sexual relationships of women before, between, and after marriages could feel more comfortable being pregnant during more of their childbearing years than women living in less open communities. However, the ease with which a women can contract sexual liaisons does not directly translate into a socially sanctioned pregnancy and birth. Experiences of miscarriages and the duration of breastfeeding are also factors in the time during which a woman can get pregnant. The longer the breastfeeding period, the longer the possibility of lactational amenorrhoea — the time when a women is unlikely to be ovulating and therefore to get pregnant. Referred to as the ‘proximate determinants of fertility’ by demographers, myriad factors impinge on a woman's reproductive experiences.

Governmental programmes and policies that attempt to limit or promote women's fertility also affect the number of children a woman bears. For example, China's urban policy of one child per family sends a strong message to the community about the importance of controlling fertility. In contrast, when a country limits women's access to contraceptives or abortion, as some states in the US do, some women are forced to bear children they are not able to raise.

Women's fertility outcomes are also a response to international pressures. The economic crises of the 1980s and 1990s that plagued many African countries forced many Africans into extreme poverty. The recognition that poverty limits a woman's or couple's ability to care for many children leads women and men to limit the number of children they have. In Kenya, for example, where an unstable government is unable to pay international debts and secure internal peace, demographic studies conducted during the 1990s linked the decline of women's fertility to the current economic crisis. Kenyan women and men faced with growing uncertainty in their everyday lives are electing to limit their fertility.

Sheryl A. McCurdy

Bibliography

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262. Fertility (See also Abundance.)

1. antler dance archaic animal dance, preceding mating. [Br. Folklore: Brewer Dictionary, 1]
2. Anu Irish goddess of fecundity. [Irish Folklore: Briggs, 9]
3. Aphrodite goddess of fecundity. [Gk. Myth.: Parrinder, 24]
4. Astarte goddess of fecundity. [Phoenician Myth.: Jobes, 144]
5. Astarte’s dove emblem of fecundity. [Phoenician Myth.: Jobes, 466]
6. Atargatis’ dove emblem of fecundity. [Hittite Myth.: Jobes, 466]
7. Athena Athens’ patroness; goddess of war and fecundity. [Gk. Myth.: Parrinder, 33; Kravitz, 40]
8. Baal chief male god of Phoenicians; the generative principle. [Phoenician Rel.: Parrinder, 38]
9. Bacchus’ cup symbolizes fecundity. [Gk. Myth.: Jobes, 397]
10. Bona Dea goddess of fertility; counterpart of Faunus. [Rom. Myth.: Zimmerman, 43]
11. breast symbol of nourishment and fecundity. [Ren. Art: Hall, 52]
12. Cernunnos horned deity of fecundity, associated with snakes. [Celtic Myth.: Parrinder, 58]
13. Cerridwen nature goddess whose magical cauldron was misused. [Celtic Myth.: Parrinder, 58]
14. Chloë beloved maiden, goddess of new, green crops. [Gk. Myth.: Parrinder, 62]
15. Clothru Irish goddess of fertility. [Irish Myth.: Jobes, 349]
16. clover symbolizes fecundity. [Folklore: Jobes, 350]
17. coconut presented to women who want to be mothers. [Ind. Folklore: Binder, 85]
18. Cybele nature’s fruitfulness assured by orgiastic rites honoring her. [Phrygian Myth.: Parrinder, 68; Jobes, 400]
19. Dôn goddess of fecundity; Welsh equivalent of Irish Danu. [Brythonic Myth.: Leach, 321; Jobes, 461]
20. Dag (h )da god of abundance, war, healing. [Celtic Myth.: Parrinder, 68; Jobes, 405]
21. Dagon (Dāgan ) fish-corn god symbolizing fecundity and abundance. [Babyl. Myth.: Parrinder, 71; Jobes, 405]
22. Demeter goddess of fecundity. [Gk. Myth.: Jobes, 429–430]
23. double ax emblem of fecundity. [Folklore: Jobes, 163]
24. figs, garland of a traditional pictorial identification of Pan, pastoral god of fertility. [Gk. Myth.: Jobes, 373]
25. fish signifies fecundity. [Mexican Folklore: Binder, 17]
26. flowers and fruit, garland of traditional headdress of Pomona, goddess of fertility. [Rom. Myth.: Jobes, 373]
27. flowers, garland of traditional pictorial identification of Flora, goddess of flowers and fertility. [Rom. Myth.: Jobes, 373]
28. Freya goddess of agriculture, peace, and plenty. [Norse Myth.: Payton, 257]
29. grape leaves, garland of traditional headdress of Bona Dea, goddess of fertility. [Rom. Myth.: Jobes, 373]
30. green symbol of fruitfulness. [Color Symbolism: Jobes, 356]
31. horn believed to promote fertility. [Art: Hall, 157]
32. horse symbolizes fecundity. [Bengali Folklore: Binder, 67]
33. Lavransdatter, Kristin gives birth to eight sons in ten years. [Nor. Lit.: Kristin Lavransdatter, Magill I, 483–486]
34. Mylitta goddess of fertility. [Babyl. Myth.: Leach, 776]
35. old woman who lived in a shoe what to do with so many children? [Nurs. Rhyme: Opie, 434]
36. Ops Sabine goddess of fecundity. [Rom. Myth.: Brewer Dictionary, 782]
37. orange blossoms symbolic of bride’s hope for fruitfulness. [Br. and Fr. Tradition: Brewer Dictionary, 784]
38. Pomona goddess of gardens and fruit trees. [Rom. Myth.: Zimmerman, 218]
39. pomegranate indicates abundance. [Heraldry: Halberts, 36]
40. rabbit symbol of fecundity. [Animal Symbolism: Mercatante, 125–126]
41. Rhea worshiped orgy and fertility; mother of Zeus, Poseidon, Hera, Hades, Demeter, and Hestia. [Gk. Myth.: NCE, 1796]
42. rhinoceros horn in powdered form, considered powerful fertility agent. [Eastern Culture: Misc.]
43. waxing moon only effective time for sowing seeds. [Gardening Lore: Boland, 31]
44. yellow color of fecundity, relating to yellow sun and earth. [Eastern Color Symbolism: Binder, 78]

fertility drug any of a variety of substances used to increase the possibility of conception and successful pregnancy. Different methods are used to correct or circumvent the many different functional disorders of both males and females that can interfere with conception and childbearing (see infertility ). The term fertility drug primarily refers to drugs that mimic or stimulate production of a hormone necessary for conception, but it may also be used to refer to the hormones themselves, when they are administered as part of a program of infertility treatment.

The most common cause of female infertility is failure to ovulate. In certain cases this can be corrected with the drug clomiphene citrate (Clomid, Serophene). Introduced in 1967, clomiphene stimulates the release of the gonadotropic hormones : follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH functions to stimulate the ovarian follicle (the egg and its surrounding fluid and hormones); LH triggers ovulation. In some studies, clomiphene has been associated with an increased risk of ovarian cancer. Clomiphene is also used to stimulate spermatogenesis in men with low sperm counts.

Human menopausal gonadotropin, or menotropin (Pergonal), introduced in 1970, is an extract from the urine of menopausal women. It contains FSH and LH and encourages ovulation. It is often given together with human chorionic gonadotropin (HCG), a hormone secreted by the placenta during pregnancy and obtained from the urine of pregnant women. Its action is similar to that of luteinizing hormone. In males the same combination is given to increase testosterone production, which in turn increases sperm production.

Urofollitropin (Metrodin) is essentially follicle-stimulating hormone without luteinizing hormone. It is used especially in women with polycystic ovary syndrome, who tend to have too little FSH and too much LH. A frequent result of ovulation induced by these drugs is the production of more than one ovum (egg) in a month, and subsequent multiple births .

Progesterone is a female sex hormone that induces secretory changes in the lining of the uterus essential for successful implantation of a fertilized egg. It is released by the ovary after the ovum is released. It is administered in cases where fertilization of the ovum does occur but where there is evidence that the uterine lining is unable to support the developing fetus, as in repeated miscarriages or bleeding during pregnancy.

See also DES (diethylstilbestrol).

fertility, fertility rate The actual level of childbearing of an individual or population. There are different ways of measuring the fertility of a population. The simplest measure, the crude birth-rate, relates the number of live births in a given year to the total population size in that year. More complex measures relate the year's births to more restricted populations, usually childbearing women, to yield a better index of underlying fertility. The denominator may be all women of childbearing years (commonly set at 15 to 44) or women in more specific age-bands (age-specific fertility rates). Fertility rates may be combined with mortality rates to generate an overall reproduction rate.

Measures relating fertility to population (whether total or specific) in a given year are termed period rates. Arguably of more value in detecting fertility trends are so-called cohort rates. These measure the births to women grouped according to year of birth (birth cohorts) or age at marriage (marriage cohorts). Cohort fertility rates can reveal variations in the timing of childbearing between different cohorts and indicate whether changes in period measures are due to changes in the spacing of births or to changes in overall family size (though final figures can only be obtained after a lengthy period).

Historically there has been a long-term decline in levels of fertility in industrial societies, a decline that is associated with economic development and restructuring, reductions in child mortality, changes in welfare provision and the economic and social value of children, and the changing social position of women.

fertility
1. (fecundity, fruitfulness) The reproductive capacity of an organism, i.e. the number of eggs that develop in a mated female over a specified period. It is usually calculated at the stage when this number is readily observable (i.e. in oviparous animals when eggs are laid and in viviparous animals when young are born), although strictly speaking it applies from the time that fertilization occurs. Sometimes the term ‘fertility’ is applied only to the production of fertilized eggs (ova), while ‘fecundity’ is used for the production of offspring, so excluding those embryos which fail to develop.

2. The condition of a soil relative to the amount and availability to plants of elements necessary for plant growth. Soil fertility is affected by physical elements (e.g. supply of moisture and oxygen) as well as by the supply of chemical plant nutrients.

fertility. The power to support vegetation and bring forth the young of living creatures was, in different Celtic traditions, dispersed between sacred objects and different personalities. The cauldron often implies fertility in different Celtic traditions. Female deities may foster fertility more often than male deities, but either gender may pertain; there is no one fertility-god or goddess. Rosmerta appears to be a fertility-goddess, and aspects of the representations of Cernunnos imply fertility functions. The Romano-Gaulish trinity known as Matres are both fertile mothers and virgins. Other figures associated with fertility include Aacute;ine (1), Brigit, Cymidei Cymeinfoll, the Dagda, and Dôn. The Fomorians of Ireland's pseudo-history Lebor Gabála. [Book of Invasions] have associations both with blight and with fertility.

fertility
1. The condition of a soil relative to the amount and availability to plants of elements necessary for plant growth. Soil fertility is affected by physical elements, e.g. supply of moisture and oxygen, as well as by the supply of chemical plant nutrients.

2. (fecundity, fruitfulness) The number of eggs that develop in a mated female over a specified period. It is usually calculated at the stage when this number is readily observable (i.e. in seed plants when seeds are borne), although strictly speaking it applies from the time that fertilization occurs. Sometimes the term ‘fertility’ is applied only to the production of fertilized eggs (ova), while ‘fecundity’ is used for the production of fruit (in angiosperms) so excluding those embryos which fail to develop.

fertility
1. The potential capability of an organism to reproduce itself. In sexually reproducing plants and animals it is the number of fertilized eggs produced in a given time. For practical purposes this usually cannot be measured, and the only reliable indicators are the numbers of mature seeds produced, eggs laid, or live offspring delivered. However, these measures are strictly referred to as fecundity, since they exclude fertilized embryos that have failed to develop.

2. The relative ability of a soil to support plant growth. It consists of both physical factors, e.g. particle size and moisture content, and chemical factors, e.g. concentration and availability of nutrients.

fertility (fecundity, fruitfulness) The reproductive capacity of an organism, i.e. the number of eggs that develop in a mated female over a specified period. It is usually calculated at the stage when this number is readily observable (i.e. in oviparous animals when eggs are laid and in viviparous animals when young are born), although strictly speaking it applies from the time that fertilization occurs. Sometimes the term ‘fertility’ is applied only to the production of fertilized eggs (ova), while ‘fecundity’ is used for the production of offspring, so excluding those embryos which fail to develop.

FERTILITY

FERTILITY. SeeChildbirth and Reproduction ; Demography and Demographic Trends .

Fertility. See Childbirth; Child Rearing.

fertility see infertility .

fertility •banditti, bitty, chitty, city, committee, ditty, gritty, intercity, kitty, nitty-gritty, Pitti, pity, pretty, shitty, slitty, smriti, spitty, titty, vittae, witty •fifty, fifty-fifty, nifty, shifty, swiftie, thrifty •guilty, kiltie, silty •flinty, linty, minty, shinty •ballistae, Christie, Corpus Christi, misty, twisty, wristy •sixty •deity, gaiety (US gayety), laity, simultaneity, spontaneity •contemporaneity, corporeity, femineity, heterogeneity, homogeneity •anxiety, contrariety, dubiety, impiety, impropriety, inebriety, notoriety, piety, satiety, sobriety, ubiety, variety •moiety •acuity, ambiguity, annuity, assiduity, congruity, contiguity, continuity, exiguity, fatuity, fortuity, gratuity, ingenuity, perpetuity, perspicuity, promiscuity, suety, superfluity, tenuity, vacuity •rabbity •improbity, probity •acerbity • witchetty • crotchety •heredity •acidity, acridity, aridity, avidity, cupidity, flaccidity, fluidity, frigidity, humidity, hybridity, insipidity, intrepidity, limpidity, liquidity, lividity, lucidity, morbidity, placidity, putridity, quiddity, rabidity, rancidity, rapidity, rigidity, solidity, stolidity, stupidity, tepidity, timidity, torpidity, torridity, turgidity, validity, vapidity •commodity, oddity •immodesty, modesty •crudity, nudity •fecundity, jocundity, moribundity, profundity, rotundity, rubicundity •absurdity • difficulty • gadgety •majesty • fidgety • rackety •pernickety, rickety •biscuity •banality, duality, fatality, finality, ideality, legality, locality, modality, morality, natality, orality, reality, regality, rurality, tonality, totality, venality, vitality, vocality •fidelity •ability, agility, civility, debility, docility, edibility, facility, fertility, flexility, fragility, futility, gentility, hostility, humility, imbecility, infantility, juvenility, liability, mobility, nihility, nobility, nubility, puerility, senility, servility, stability, sterility, tactility, tranquillity (US tranquility), usability, utility, versatility, viability, virility, volatility •ringlety •equality, frivolity, jollity, polity, quality •credulity, garrulity, sedulity •nullity •amity, calamity •extremity • enmity •anonymity, dimity, equanimity, magnanimity, proximity, pseudonymity, pusillanimity, unanimity •comity •conformity, deformity, enormity, multiformity, uniformity •subcommittee • pepperminty •infirmity •Christianity, humanity, inanity, profanity, sanity, urbanity, vanity •amnesty •lenity, obscenity, serenity •indemnity, solemnity •mundanity • amenity •affinity, asininity, clandestinity, divinity, femininity, infinity, masculinity, salinity, trinity, vicinity, virginity •benignity, dignity, malignity •honesty •community, immunity, importunity, impunity, opportunity, unity •confraternity, eternity, fraternity, maternity, modernity, paternity, taciturnity •serendipity, snippety •uppity •angularity, barbarity, bipolarity, charity, circularity, clarity, complementarity, familiarity, granularity, hilarity, insularity, irregularity, jocularity, linearity, parity, particularity, peculiarity, polarity, popularity, regularity, secularity, similarity, singularity, solidarity, subsidiarity, unitarity, vernacularity, vulgarity •alacrity • sacristy •ambidexterity, asperity, austerity, celerity, dexterity, ferrety, posterity, prosperity, severity, sincerity, temerity, verity •celebrity • integrity • rarity •authority, inferiority, juniority, majority, minority, priority, seniority, sonority, sorority, superiority •mediocrity • sovereignty • salubrity •entirety •futurity, immaturity, impurity, maturity, obscurity, purity, security, surety •touristy •audacity, capacity, fugacity, loquacity, mendacity, opacity, perspicacity, pertinacity, pugnacity, rapacity, sagacity, sequacity, tenacity, veracity, vivacity, voracity •laxity •sparsity, varsity •necessity •complexity, perplexity •density, immensity, propensity, tensity •scarcity • obesity •felicity, toxicity •fixity, prolixity •benedicite, nicety •anfractuosity, animosity, atrocity, bellicosity, curiosity, fabulosity, ferocity, generosity, grandiosity, impecuniosity, impetuosity, jocosity, luminosity, monstrosity, nebulosity, pomposity, ponderosity, porosity, preciosity, precocity, reciprocity, religiosity, scrupulosity, sinuosity, sumptuosity, velocity, verbosity, virtuosity, viscosity •paucity • falsity • caducity • russety •adversity, biodiversity, diversity, perversity, university •sacrosanctity, sanctity •chastity •entity, identity •quantity • certainty •cavity, concavity, depravity, gravity •travesty • suavity •brevity, levity, longevity •velvety • naivety •activity, nativity •equity •antiquity, iniquity, obliquity, ubiquity •propinquity