Population-based studies of human sexuality investigate the sexual expression of women and men at different stages of the life course and across groups and societies. Sexual expression is composed of sexual functions, or capacities, of males and females; sexual behaviors, both partnered and alone; and sexual attitudes–interests, preferences, and beliefs about sexuality. Identifying and investigating biological, psychocognitive, demographic, and sociocultural determinants of sexual expression as well as the interrelationships among sexual attitudes, behavior, and function are a central concern. This research also assesses the consequences of sexual expression, which include but are not limited to effects on wellbeing, health, relationship quality, sexual satisfaction, fertility, the stability of sexual partnerships, and the transmission of sexually transmitted infections (STIs), especially HIV and AIDS.
In the 1990s the increasing availability of large-scale probability samples on sexual behavior, a result of international concern about HIV/AIDS, facilitated advances in the study of human sexuality. Studies employing nationally representative data on adult sexual behavior were published for several developed countries, including Great Britain, Finland, France, and the United States, along with cross-national comparisons of European, African, and Asian countries. The United States in particular has conducted additional large-scale, representative-sample surveys featuring modules on sexual behavior–the National AIDS Behavioral Survey, the National Survey of Adolescent Males, the National Survey of Men, the National Survey of Women, the General Social Survey, and the National Longitudinal Study of Adolescent Health–which represent vast improvements over research derived from convenience, local community, or self-selected samples.
These studies also marked the emergence of human sexuality as a distinct topic in population studies. Previously, many researchers had focused only on the limited set of sexual behaviors that are consequential for fertility outcomes (e.g., frequency of coitus, out-of-wedlock fertility, contraceptive practices). Lacking basic information about sexual attitudes and behavior, researchers were spurred by the threat of HIV/AIDS in the 1990s to develop a comprehensive approach focused on sexual expression. Many of these studies collected information on partnered sex, an approach that captured variation in status (e.g., married versus nonmarried), gender, and patterns of multiple partners or sexual networks.
Sexual expression has sociocultural, psychocognitive, emotional, physiological, and behavioral dimensions. It encompasses the content of sexual action: how people think about sex, what they do sexually, and the concomitant psychophysiological states. Sexual attitudes are the beliefs, preferences, and interests individuals express about sexual issues, conduct, and partners. Sexual behaviors specify the sexual practices individuals engage in alone, with another person, or with multiple others. Sexual functioning refers to how individuals experience sexual desire, pleasure, and other psychophysiological states associated with the sexual response cycle.
Although researchers recognize the significance of biological factors, particularly physiology, maturation, and aging, on sexuality, those working from a population perspective tend to emphasize the social control, or social organization, of sexuality. Of particular importance are institutional controls–religion, kinship, law, and medicine–and traditional demographic attributes, such as ethnicity, which imbue cultural meanings into sexual behavior, thus defining the proximate costs and benefits of sexual choices. Population-based research increasingly focuses on sexual partnerships as well as partnership networks as a key feature of sexual expression.
Reflecting the social and institutional bases of sexuality, a central research area in human sexuality is the comparative analysis of sexual expression. Key sources of variation include cross-national, intrasocietal, historical, and life-course stage differences. Because the United States currently has the most comprehensive data on sexual expression, including national probability samples of adolescents, adults, and high-risk groups, the following sections rely heavily on illustrative U.S. results. Reflecting the dominant research strategies in the literature, this section reviews each facet of sexual expression separately, although it should be kept in mind that sexual functioning, behavior, and attitudes are interrelated phenomena.
For example, homosexuality, which has attracted heated debate about its meaning, prevalence, and etiology, can be decomposed into three dimensions: desire, behavior, and identity. Tables 1a and 1b provide an overview of the prevalences of these dimensions. However, it should be stressed that asking people about homosexuality is fraught with difficulties because its stigmatization in popular opinion is likely to produce systematic biases towards underreporting in responses to survey questions.
Sexual attitudes. Sexual attitudes refer to the beliefs, preferences, and interests individuals hold about sexual conduct. Although sexual attitudes are culturally contingent, scholars have focused primarily on a limited set of attitudes: premarital sex, teenage sex, extramarital sex, and homosexuality. Research concentrates on two topics: (1) sexual permissiveness and (2) normative orientations. The first approach, pioneered by Ira Reiss, assesses levels of permissiveness for various sexual issues, including premarital sex and extramarital sex. In contrast, the normative orientations approach does not assume a one-dimensional scale of permissiveness; instead, it focuses on identifying different types of sexual regimes. Edward O. Laumann and colleagues (1994), for example, found three major classes in the United States: traditional, relational, and recreational orientations. Cross-national variation is even more dramatic. Eric D. Widmer et al. (1998) grouped countries into one of three major sexual regimes with reference to attitudes toward nonmarital sex–teen permissives (Germany, Austria, Sweden, Slovenia), sexual conservatives (United States, Ireland, Poland), and homosexual permissives (Netherlands, Norway, Czech Republic, Canada, Spain)–along with a heterogeneous residual category composed of countries with moderate sexual attitudes (Australia, Great Britain, Hungary, Italy, Bulgaria, Russia, New Zealand, Israel) and two isolates (Japan, Philippines).
Sexual behaviors. Sexual behavior covers autoeroticism, partnered sex, and the relationship between these two dimensions of sexual life. The central finding on autoerotic activity is the much greater incidence of such activity in men than in women.
Major aspects of partnered sex include the number of sexual partners, the frequency of sex, sexual practices, the relational dimensions of sexual behavior, homosexuality, formative sexual experiences, and risk-related behaviors. Table 2 shows that partnered sex among Americans is remarkably conventional. The vast majority of Americans have only one sex partner over a one-year period, have few sexual partners in adulthood, have sex only occasionally, and engage in a limited set of sexual practices. Despite what appears to be a modest amount of sex, Americans are generally happy with their sex lives and their partners. Laumann et al. (1994) also focus on the prevalence of sexual practices relevant for the transmission of disease, such as vaginal, oral, and anal sex, as well as how certain sexual behaviors are correlated with types of sexual partnerships (e.g., marriages and monogamy). Findings about the prevalence of homosexuality and the impact of formative sexual experiences, such as sexual debut, forced sex, and adult and adolescent sexual contacts with children, have been published as well. Finally, a central topic in the demography of sexual behavior is the study of other risk-related behaviors of HIV/AIDS transmission, such as condom use, having paid sex, multiple partnering, and prior experience with STIs.
Sexual functioning. Sexual functioning covers individuals' experiences with sexual desire, sexual pleasure, and psychophysiological changes associated with the sexual response cycle. Demographic research focuses on three topics: sexual maturation, sexual problems, and the use of contraceptives, drugs, and sterilization procedures. Because the transition to sexual maturity has extensive implications for sexual behavior and fertility, researchers are interested in trends, variation, and determinants of the pubertal development of males and females. Also associated with aging, but in a surprisingly more limited way than was expected, an emerging area of research focuses on sexual dysfunctions–disturbances in sexual desire and in the psychophysiological changes associated with the sexual response cycle. Laumann, Anthony Paik, and Raymond C. Rosen (1999) concluded that sexual problems are quite common among the U.S. adult population 18 to 59: More than 40 percent of adult women and 30 percent of adult men reported sexual problems of several months' duration during a 12-month period. Research on the cross-national and historical patterning of sexual problems is scanty, but new studies under way in 2003 will begin to remedy this situation.
A central development regarding sexual functioning is the availability of new technologies–contraceptives, drugs, and sterilization procedures–that directly affect the sexual response or reproductive cycles. Contraceptive and sterilization practices are traditionally covered in the study of fertility control, yet these technologies are significant for human sexuality, since their adoption severs the link between sex and fertility in many countries and directly affects sexual function. Another technological development is the introduction of drugs designed to enhance sexual performance, but little is known about this trend.
Determinants of Sexual Expression
When investigating determinants, most researchers have focused on one aspect or a few aspects of sexual expression. Alternatively, sexual expression can be approached as an integrated entity in which sexual attitudes and functioning act as proximate determinants for partnered and autoerotic sexual behaviors. Laumann and Yoosik Youm (2001) identify four broad classes of determinants, displayed in Figure 1:(1) individual preferences for particular sexual experiences, (2) state of physical health and capacity to engage in particular sexual activities, (3) competence to initiate and maintain social relationships of various sorts, and (4) social opportunities to secure appropriate sex partners. Subjective preferences refer to interests and beliefs about sexual conduct and derive from normative orientations. People with impaired physical or mental health (e.g., erectile or other sexual dysfunctions) may not be able to engage in certain patterns of sexual expression regardless of their preferences. Social competence refers to individuals' skills at and resources for initiating and maintaining ongoing sexual partnerships. These skills include communication and people-handling skills, time, money and goods, and reputation. Finally, these individual-level attributes are theorized to jointly affect the social contexts, or opportunities, in which sexual behavior is embedded. These contexts include the type of partnerships individuals are able to form, mode of meeting, participation in certain social scenes, and social membership factors.
Outcomes of Sexual Expression
There are substantial literatures linking specific aspects of sexual expression to health-related outcomes, such as the transmission of STIs, behavioral responses to HIV/AIDs, well-being, and family-related outcomes, including marital and nonmarital fertility, fertility control (e.g., abortion), and the dissolution of sexual partnerships. This section focuses on two of these outcomes: STIs/HIV and abortion.
STIs/HIV. An emerging paradigm in the study of the transmission of STIs and HIV is the integration of network approaches with survey data on partnered sex. Utilizing Martina Morris's (1993) epidemiological models, Laumann and Youm (1999) not only analyzed individual-level risk factors related to sexual expression, such as the number of partners, but also accounted for the potential infection status of partners as well as transmission dynamics related to the spread of STIs across socially distinct populations. A second area in the demography of human sexuality is the study of responses to the HIV/AIDs epidemic.
Abortion. The demography of human sexuality has led to better information linking sexual expression to fertility control. Before the emergence of national data sets on sexual behavior, little was known about this link, since few data sets collected comprehensive data on sexual attitudes and behavior. In one of the few national studies of abortion in the United States, Robert T. Michael (2001) found that economic and social incentives for having children, as well as having sexual attitudes against the legalization of abortion, had strong negative effects on the likelihood of this practice. Comparing several high-quality surveys with data reported by abortion providers and compiled by the Alan Guttmacher Institute (AGI), Elise F. Jones and Jacqueline Darroch Forrest (1992) found that survey-reported abortions were systematically and substantially underestimated. Indeed, underreporting of socially stigmatized, sex-related behaviors is a general methodological problem for research on the demography of human sexuality.
Future Issues for the Demography of Human Sexuality
Professional and public interest in human sexuality was sparked most recently by the threat of HIV/AIDS. In addition to the growing prevalence of HIV/AIDS, several trends highlight the continuing need for population-based data on sexual behavior. As an example, the United States underwent dramatic changes in sexual attitudes, sexual practices, and
marital behavior in the last decades of the twentieth century. U.S. sexual attitudes continue to be liberalized, the median number of lifetime partners continues to increase, and individuals spend as much as one-quarter of their pre-age-60 adult lives as sexually active singles. Taken together, these trends suggest that sexual expression in the United States is still changing, perhaps making sexual markets more important than marriage markets. Indeed, HIV/AIDS and the changing nature of sexual expression will continue to make the demography of human sexuality an important research concern.
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Edward O. Laumann