J. Richard Udry

Biological predispositions and social control in adolescent sexual behavior.

This paper develops biosocial models of adolescent sexuality that combine traditional sociological models with models derived from a biological theory of hormone effects. Data are presented from a representative 1982 sample of 102 males and 99 females drawn from grades 8 9 and 10 in public schools in a southern US city and ranging in age from 13 to 16 years old. Although the sociological models alone look quite satisfactory the combined models are stronger and give a different picture of the determinants of adolescent sexuality. The combined models show not only additive contributions of sociological and biological variables but interactions between sociological and hormonal variables. Some sociological relationships are shown to be spurious. In other cases sociological predictors are shown to be endogenous to biological predictors. (authors)

Parental Marital Status Effects on Adolescent Sexual Behavior.

Data from a panel study of virgin adolescents first interviewed in junior high school confirm previous findings by others that parental marital status and its changes are related to initiation of coitus by young adolescents. 1405 out of an eligible 1923 adolescents in 4 junior high schools (73%) were interviewed and filled out a confidential questionnaire in their own homes. 2 years later in 1982 82% of the the original interviewees were reinterviewed. Compared to the experience of adolescents in stable households with 2 natural parents the state of being in a mother-only household predicts a higher probability of subsequent transition to coitus for girls. Only the disruption of the 2-parent household (i.e. in a marital separation) between interviews predicts transition to coitus for boys. Parental marital status has the same effects on other age-graded delinquencies (e.g. smoking drinking alcoholic beverages driving a car without the owners permission) that it has on initiation of coitus. Pre-existing differences in other dimensions e.g. mothers education age of mother are examined as well: only 2 predicted coital transition. This finding supports conceptualizing marital status effects on adolescent coitus as parental loss of control over the whole class of age-graded delinquencies rather than a specific sexual effect. The effect of a marital separation appears to begin at around age 10 for girls. Single-parent households being a growing phenomenon there is likely to be an effect on the incidence of adolescent pregnancy.

Smart Teens Don't Have Sex (or Kiss Much Either)

PURPOSE To examine the relationship between an intelligence measure and a wide spectrum of partnered sexual activity ranging from holding hands to sexual intercourse among adolescents. METHOD Analyses are based on two separate samples of adolescents. The core sample of the National Longitudinal Study of Adolescent Health (Add Health) includes approximately 12,000 adolescents enrolled in the 7th to 12th grades. The Biosocial Factors in Adolescent Development projects followed approximately 100 white males and 200 black and white females over 3- and 2-year periods, respectively. Both studies used the Peabody Picture Vocabulary Test (PPVT) as an intelligence measure, and confidential self-reports of sexual activity. Logistic regression models were used to examine the relationship between PPVT scores and coital status in Add Health data; proportional hazard models were used to examine the timing of initiation of noncoital and coital activities as a function of PPVT scores in the Biosocial Factors sample. RESULTS Controlling for age, physical maturity, and mothers education, a significant curvilinear relationship between intelligence and coital status was demonstrated; adolescents at the upper and lower ends of the intelligence distribution were less likely to have sex. Higher intelligence was also associated with postponement of the initiation of the full range of partnered sexual activities. An expanded model incorporating a variety of control and mediator variables was tested to identify mechanisms by which the relationship operates. CONCLUSIONS Higher intelligence operates as a protective factor against early sexual activity during adolescence, and lower intelligence, to a point, is a risk factor. More systematic investigation of the implications of individual differences in cognitive abilities for sexual activities and of the processes that underlie those activities is warranted.

BIOLOGICAL LIMITS OF GENDER CONSTRUCTION

A biosocial theory of gender is constructed on both the macro and micro levels. A micro-model of within-sex differences among females integrates the biological model current in primatology with the prevailing social science model. It shows how sex differences in hormone experience from gestation to adulthood shape gendered behavior (that is, behavior that differs by sex). On the macro level, this model also illustrates how socialization and environment shape gendered behavior. It then demonstrates how hormone experiences can facilitate or dampen the effects of socialization and environment on gendered behavior. Data are from a sample of women who were studied from before they were born to the end of their third decade. I speculate about the constraints placed by biology on the social reconstruction of gender

Serum androgenic hormones motivate sexual behavior in adolescent boys

In order to separate hormonal from social effects on adolescent male sexual behavior, serum hormone assays were performed and questionnaire data on sexual motivation and behavior were collected on a representative sample of 102 boys in grades 8, 9, and 10 of a public school system. Free testosterone was a strong predictor of sexual motivation and behavior, with no additional contribution of other hormones. Including measures of pubertal development and age (indexing the effects of social processes) indicated no additional effects. Free testosterone, therefore, appears to affect sexual motivation directly and does not work through the social interpretation of the accompanying pubertal development.

Benefits of Being Attractive: Differential Payoffs for Men and Women

This study used attractiveness ratings of about 601 males and 745 females based on high school annual pictures to predict marital and socio-economic status 15 yr. later. Attractiveness gets females highly educated husbands with high income, but no benefits in occupational status or own income. It also reduces the probability of remaining unmarried. For males, attractiveness interferes with achievement of status.

Risk Assessment of Adolescents With Same-Sex Relationships

PURPOSE To compare the risk status on health and behavior for those with same-sex partners and those without. METHODS Add Health data provide a sample of 20,745 adolescents in grades 7 through 12 interviewed at home. The risk statuses of respondents with no partners, same-sex-only partners, and partners of both sexes were compared to respondents with opposite-sex partners only. Respondents were evaluated on selected personal and social attributes (verbal IQ, family structure, masculinity, popularity), and risk status (substance use, depression, suicidal thoughts, anal sex, general delinquency, being physically attacked, perceived risk of being killed or getting AIDS). Data were analyzed by logistic and linear regression using STATA to adjust for clustering and sampling weights. RESULTS Compared to boys with opposite-sex-only partners, boys with same-sex-only partners were at high risk for emotional problems, but not delinquency or substance use. Boys with partners of both sexes were at high risk for delinquency and substance use, but not for emotional problems. Neither group of boys with same-sex partners is at high risk of being attacked compared to those with opposite-sex partners only. Girls with only same-sex partners are never a high-risk group, while girls with partners of both sexes are the high-risk category in every case. CONCLUSIONS Adolescents with same-sex-only partners do not resemble those with partners of both sexes in risk status. Combining the two categories obscures the unique risk profile of those with both-sex partners, and obscures the low risk on most variables but the high emotional risk of boys with only same-sex partners.

Mothers' Influence on the Sexual Behavior of Their Teenage Children.

Multivariate techniques are used to examine the influence of mothers sexual experiences as teenagers on their teenage childrens current sexual behaviors. Little of the demonstrated relationship is transmitted through differential attitudes or communication patterns of mothers with differing early sexual experience. For girls there is a reason to believe that the correlation between the mothers early behavior and the daughters current behavior is transmittedd partly via their giological relationship. The population for this study comprizes junior high school students in an urban area of a southern state. The average age of the students was about 14 with age span of 11 to 17 years of age. By race 36% were white males 13% black males 38% white females and 13% black females. Cross-tabulations and correlations are used to explore the relationship between the mothers early behavior and the teenagers current behavior. This research has confirmed the hypothesis that the sexual behavior of the mother when she was an adolescent is related to he current sexual behavior of her child. For boys insisgnificant amounts of influence by mothers early experience are mediated either via the sons developmental atiming or via the mothers attitudes toward sexuality.

The nature of gender

I explain a biosocial model of women’s gendered behavior (behavior on which the sexes differ). This model integrates a macro sociological theory with a biological theory derived from primate behavior. The sociological model is designed to explain changes in the relationship between sex and behavior over time or between groups. The biological model is designed to explain individual within-sex variance and between-sex variance in gendered behavior in a cohort. Results from an original study are presented to demonstrate that within-sex variance in women’s gendered behavior is explained well by the primate model. I conclude that human nature is gendered. The implications of this conclusion are explored for demographic and other social science research.

A cross-cultural examination of the relationship between ages at menarche, marriage, and first birth

Recent work with samples of black and white urban American women showed a clear behavioral sequence relating age at menarche to age at first intercourse to age at first birth. This paper shows that the linking of ages at menarche, intercourse, marriage, and first birth is a pattern which occurs in very diverse cultures. We present confirmatory data from the United States, Belgium, and Pakistan, and from Malay and Chinese women in Malaysia. We interpret our findings as indicating a biological process leading to (a) social interpretations of readiness for reproduction, and (b) persisting biological differences between early and late maturing women.