Family Demography

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Family demography is the study of the composition of families and of the transitions individuals make into and out of various types of families. Family composition includes factors such as the number of family members, their ages, marital and cohabitation status, and relationship to other family members. Transitions include life-course characteristics such as the timing and duration of cohabitation, marriage, separation, divorce, and remarriage.

Demographers developed the field of family demography during the mid-twentieth century as a means of better understanding the number and timing of births. In the 1950s and 1960s, when most births in Western countries occurred within marriages, family demographers mainly studied the nuclear family of husband, wife, and children. But as the family changed in similar ways throughout most Western countries, family demographers broadened their focus to include adults living independently, single-parent families, cohabitating couples (unmarried couples living together), and rates of divorce and remarriage. As birth rates declined during the second half of the twentieth century, family demographers began to study these family forms independent of their impact on fertility.

In 1940 the U.S. Bureau of the Census published its first report classifying families into different types; categories included normal (meaning a married couple), other male headed, and all female headed. Labeling families with a married husband and wife "normal" reflects the dominance of the nuclear family in the mid-twentieth century. As that dominance faded, the bureau changed its terminology, broadened its categories, and began to collect more information in its monthly Current Population Survey. In the 1970s surveys conducted for other purposes, such as the Panel Study of Income Dynamics, provided useful information, and in the 1980s and 1990s specialized surveys such as the National Survey of Families and Households provided the first detailed information about cohabitation. In the United Kingdom one of the first sets of papers on family demography was presented at a 1983 meeting of the British Society for Population Studies. Family demographers in Western Europe, including Louis Roussel and Ron Lesthaeghe, published influential books and articles during the 1980s and 1990s about the enormous changes in European families.

At about the middle of the twentieth century, demographers noted a demographic transition involving a long-term decline in fertility and mortality rates. After 1965, as the post–World War II baby boom faded, family demographers began to write of a "second demographic transition." This transition refers to the set of changes in family formation and childbearing including increases in independent living among young adults, extensive premarital cohabitation, older ages at marriage, high levels of divorce, fertility at or below the population replacement levels, and increased childbearing out-side of marriage. Economists such as Gary Becker theorized that changes in family formation occurred because the economic gains of the traditional breadwinner–homemaker marriage decreased: As women's employment opportunities rose, so did the cost in lost wages of remaining a full-time housewife. Ideational theorists such as Lesthaeghe and Johan Surkyn asserted that the second demographic transition reflected a long-term shift in societal values toward greater individual autonomy and self-fulfillment, and away from moral obligations to family and society. Just as the economic changes were said to reduce the gains in efficiency that being married provides, the ideational changes were said to reduce the satisfaction and fulfillment that people gained from being married and raising children.

Independent Living

At the beginning of the twentieth century, most young adults lived at home until marriage. The prevailing values of the time discouraged independent living, many families relied on young adults' contributions to household income, and a shortage of housing for single people limited opportunities for leaving the family home. All of these factors changed after mid-century, and the typical age at marriage rose. As a result of these changes, the percentage of young adults living by themselves or with roommates increased during the last half of the twentieth century. The rise in divorce rates through the 1960s and 1970s also resulted in a greater number of formerly married adults living on their own.

At the turn of the twentieth century, a majority of the elderly lived in their children's homes. This, too, changed during the twentieth century, as increased life expectancies and greater affluence among the elderly led to a substantial increase in the number of older people living alone. Yet even though most of the elderly lived apart from their children by the year 2000, they tended to see them regularly and to provide assistance to them.


Through the 1950s age at marriage was the most important determinant of fertility in the Western countries because sexual intercourse was mostly limited to married couples. In Western countries marriage typically occurs well after young women become fertile. This delay is an important contributing factor to the relatively small family size in Western countries, even before industrialization.

Figure 1 illustrates the change in percentage of 20-to 24-year-old women and men in the United States who had ever been married, from 1890 to 1998. At the beginning of the twentieth century, marriages occurred at relatively older ages, so that fewer 20-to 24-year-olds had married. During the baby boom years of 1945 to 1965, the typical age at marriage dropped sharply, so that the proportion of young adults who had ever been married increased. After the baby boom, ages at marriage rose back to


the pre–baby boom levels for men and rose even further for women. At the end of the twentieth century, the mean age at first marriage in the United States was approximately 25 for women and 27 for men, and the percentage of ever-married young adults was at or near an historic low. Young adults in the 1990s were marrying later because higher education and early investment in a career were considered extremely important, the labor market opportunities for men without college educations had diminished, and sexual relations outside of marriage were more culturally acceptable and carried less risk of an unwanted pregnancy due to improved contraceptive technology such as the birth control pill.

Although rates decreased from the 1960s through the 1990s, marriage remained an important part of the Western family system. Throughout most of the twentieth century, at least 90 percent of all individuals eventually married in the United States, and nearly as many married in most other Western nations. Marriage rates were lowest for adults who came of age during the Great Depression of the 1930s, and highest for those who came of age during the baby boom. Joshua Goldstein and Catherine Kenney projected in 2001 that about 90 percent of white young adults in the United States would eventually marry, but that only about two-thirds of African-American young adults would. According to the U. S. Bureau of the Census, 64 percent of children in the United States lived with both biological or adoptive parents in 1996, but marriage was not as dominant a family form as it was a half-century before. More and more individuals were living in unmarried couples, single-parent families, and stepfamilies.


Prior to the last few decades of the twentieth century, cohabitation, a living arrangement in which an unmarried couple share a household, was uncommon in most Western countries except among the poor. Beginning in the 1960s, cohabitation increased among all social classes, but remained more prevalent among the less affluent and less educated. At the end of the twentieth century, a majority of young adults in the United States lived in a cohabiting relationship prior to marrying. Premarital cohabitation was even more common in many Scandinavian and Northern European countries. Cohabitation after the disruption of a marriage was also widespread. In fact, about a third of cohabiting couples in the United States in 2000 had a child from a partner's previous marriage or relationship. Cohabitation increased because of improvements in birth control, such as the introduction of the birth control pill in 1960 and the legalization of abortion in 1973; the stagnant earning prospects of young men in the 1970s and 1980s, which discouraged marriage; and the greater societal acceptance of sex outside of marriage.

The meaning of cohabitation seems to vary from couple to couple. For some, cohabitation is similar to a trial marriage. An American survey from the 1990s indicates that young adults were most likely to choose "couples can be sure they are compatible before marriage" as the primary reason a couple would decide to cohabit. Consistent with this view, most cohabiting couples in the United States in the 1990s either broke up or married within a few years. Half remained living together outside of marriage for one year or less, and only one out of ten cohabiting couples lasted as long as five years. Studies from the 1990s also show that a majority of cohabiting white couples marry before the birth of a child. For others, however, cohabitation may be a substitute for marriage: cohabiting African-American couples are less likely to marry before a child's birth than are whites. For some others, cohabitation may be merely a continuation of the single life–a living arrangement that does not require but does not preclude commitment.

Marital Dissolution

Until the mid-nineteenth century formal divorce was rare in Western nations, although informal separations undoubtedly occurred. Prior to 1858 divorces could only be granted in England by acts of Parliament and most petitioners were men who claimed their wives were adulterous. In the latter part of the nineteenth century, it became easier to gain a divorce, as the legislatures of Western countries added grounds such as habitual drunkenness or mental cruelty. Figure 2 shows the annual divorce rate in the United States from 1860 to 1998. The figure illustrates that divorce rates rose steadily but gradually until the 1960s, with the exception of a temporary surge after World War II. Between 1960 and 1980 the divorce rate virtually doubled in the United States, and similar increases occurred in other Western countries. Between 1980 and 2000 divorce rates settled on a high plateau, with perhaps a slight decline toward the end of the century. Demographers for the U.S. National Center for Health Statistics have developed projections of lifetime levels of divorce that young adults are likely to experience. These projections assume that the duration-specific rates of the early twenty-first century will continue to hold, and will therefore overestimate lifetime divorce if duration-specific rates fall in the future, and provide underestimates if these rates rise. The projections suggest that about half of all first marriages in the United States would end in divorce or permanent separation. The projections for many other Western nations are nearly as high. Divorces tend to occur early in marriages–about half occurring within the first seven years in the United States–and are more common among families with lower income, African Americans, and persons who cohabited prior to marrying, married as teenagers, or whose parents divorced.

Several social trends contributed to the rise in divorce over the second half of the twentieth century. One cultural trend was a greater emphasis on personal fulfillment, which made divorce a more acceptable option for people who felt unfulfilled by their marriages. Economic trends also affected divorce rates: Increased employment opportunities for women led to a rise in the number of wives working outside the home. Employment gave wives greater economic independence, which made divorce a feasible option for those who were unhappy in their marriages. In the 1970s and 1980s in the United States, decreasing economic opportunities for men without a college education may have reduced their earning potential and also increased the stresses on some marriages.


Before the twentieth century, most remarriages followed widowhood. But the decline in mortality rates and the rise in divorce rates during the twentieth century changed remarriage, so that by the end of the century more than nine in ten remarriages in the United States followed a divorce. According to the U.S. National Center for Health Statistics, at 2001 rates 75 percent of divorced women in the United States would remarry within 10 years. At the beginning of the twenty-first century, remarriage was more likely among non-Hispanic whites than among African Americans or Hispanic Americans. The latter two groups generally had lower income levels and therefore benefited less from the legal protections marriage provides. In addition, the lesser centrality of marriage in African-American kinship and the Catholic Church's opposition to remarriage may influence these racial and ethnic differences.


Studies at the end of the twentieth century indicate that remarriages are somewhat more likely to end in divorce than first marriages. The higher risk of divorce may result from the lack of culturally agreed upon norms for how remarried persons should interact with partners and children. In addition, people who divorce and remarry may be more likely, because of their experiences or their personalities, to end a marriage if they are having difficulties. Remarriages after divorce often create complex step-families that extend across more than one household. For example, children from previous marriages may live with or be in contact with parents in other households. Remarriages are even more likely to be preceded by a period of cohabitation than are first marriages. During the 1980s and 1990s cohabiting unions were more common and remarriages were delayed among individuals divorced five years or less.

Childbearing Outside of Marriage

In the 1950s more than 90 percent of children were born to married mothers in most Western countries. Beginning in the 1960s the percentage of children born outside of marriage began to rise. By the end of the twentieth century, one-third of all births in the United States were to unmarried mothers. In Great Britain this figure was slightly more than one-third, and in Sweden, slightly more than one-half of births were to unmarried mothers. In the United States, strong racial and ethnic differences exist in the rates of births outside of marriage; 22 percent of births to non-Hispanic whites, 42 percent to Hispanics, and 69 percent to African Americans were to unmarried mothers in 1999. A majority of these unmarried mothers in the United States formed single-parent families, but about four in ten were cohabiting with men at the time of their child's birth. Co-habitation rates for parents were even higher in Western Europe, with at least six in ten unmarried mothers cohabiting in Great Britain, and more than nine in ten in Sweden. Unmarried teenagers who give birth tend to have lower completed education, lower incomes, and less stable marriages than women who do not give birth until their twenties. Having a child as an unmarried teenager may make it difficult to complete one's education or to gain labor market experience, or teenagers who are likely to give birth may already be from disadvantaged backgrounds.

Family and Household Composition

All of the developments discussed above have greatly changed the typical household composition of families in the Western nations. In the first half of the twentieth century, the percentage of families headed by two parents increased because mortality rates fell and divorce rates were still relatively low. But in the second half of the twentieth century, the percentage of families headed by two parents decreased due to the rise in divorce, cohabitation, and childbearing outside of marriage. For example, in the United States in 1950, single parents headed only 7 percent of all families with children under 18; the corresponding figure in 2000 was 27 percent. Even the simple one-versus two-parent distinction is increasingly inadequate as an indicator of diverse household composition, because some single parents are cohabiting and some two-parent households are stepfamilies.

The living arrangements of children have changed dramatically over the course of the twentieth century. In the mid-twentieth century, about half of all children in the United States were living with a father who worked outside the home and a mother who was a full-time homemaker. By the 1990s only about one-fourth of children were living in these so-called breadwinner–homemaker families. The great increase in married women working out-side the home, as well as trends in marriage, cohabitation, and divorce rates, had produced more families with two earners as well as more single-parent families. Children at the end of the twentieth century were also more likely to live in a series of different family arrangements as their parents moved into and out of marital and cohabiting unions. At 2000 rates, for example, about 40 percent of children in the United States would witness the breakup of their parents' marriages, and about 10 percent would witness the breakup of two marriages. Moreover, about 40 percent of children would spend some time living with a parent and her or his cohabiting partner.

Children's Well-Being

The great changes in the demography of families over the course of the twentieth century affected children's well-being. In general, children living in single-parent families in 2000 had levels of wellbeing that were lower than children in two-parent families. Studies of divorce, for instance, suggest that it raises the risks of undesirable outcomes in the lives of children, such as dropping out of school, having a child before marrying, or having mental health problems. Some of these difficulties, however, may have preceded the divorce and may reflect other underlying problems (such as poverty or parental depression) rather than the number of parents in the home. Other studies suggest that a majority of children whose parents divorce will not experience serious long-term problems. Children who were living with a biological parent and a stepparent in 2000 had levels of well-being that were no better, on average, than children in single-parent households. Some studies suggest that the more transitions in family structure that a child experiences (as when parents divorce or remarry), the more difficult his or her adjustment becomes.

Research generally indicates that the increases in childbearing outside of marriage, divorce rates, and remarriage have been detrimental to children's well-being, although the long-term effects are not yet known. There is little evidence, however, that having both parents work outside the home is detrimental to children, except perhaps for infants. Other demographic trends may have been positive for children: lower fertility means that they have fewer brothers and sisters and should therefore receive more parental time and resources; rising levels of parental education may help parents ready children for school and assist them in learning.

Diversity or Decline?

There is no question that the place of marriage in the family systems of the Western nations has declined over the past half-century. Once the near universal setting for bearing and raising children, marriage rates during the twentieth century decreased as single-parenthood and cohabitation increased. Marriage is still highly valued, but it is not as necessary to be married as it used to be: In Western society in the twenty-first century, it is possible to have a long-term sexual relationship without marrying, it is possible to support oneself economically without marrying, and it is possible to shun marriage and still be respected by family and community. Marriage, then, has declined as an institution. The more difficult question is whether, more broadly, the family has declined as an institution, and on this point there is continuing debate. According to some, the family has declined because the living arrangements that have become more common are not as good for children, and possibly adults, as marriage. According to others, the family has always been changing and has weathered that change much better than its critics have feared. The growing diversity of family life, some assert, has some positive effects, such as providing greater opportunities for women who want to combine a career with raising a family.

See also: Divorce; Fertility, Nonmarital; Household Composition; Life Course Analysis; Marriage.


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Andrew J. Cherlin

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Family Demography

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