Mary Ziemba-Davis

HORMONAL CONTRIBUTIONS TO SEXUALLY DIMORPHIC BEHAVIORAL DEVELOPMENT IN HUMANS

Nineteen studies on the behavioral effects of prenatal exposure to hormones administered for the treatment of at-risk human pregnancy are reviewed. Because the role of prenatal exposure to hormones in the development of human behavioral sex differences is potentially confounded by societys differential treatment of the sexes, comparisons between exposed and unexposed subjects were evaluated and summarized separately for male and female subjects. Therefore, this review focuses on data for individuals whose prenatal hormone environments were atypical relative to what is normal for their own sex. Overall, it appears that prenatal exposure to androgen-based synthetic progestin exerted a masculinizing and/or defeminizing influence on human behavioral development, whereas prenatal exposure to natural progesterone and progesterone-based synthetic progestin had a feminizing and/or demasculinizing influence, particularly among female subjects. The data on prenatal exposure to synthetic estrogen derive primarily from subjects exposed to diethylstibestrol (DES). DES-exposed male subjects appeared to be feminized and/or demasculinized, and there is some evidence that exposed female subjects were masculinized. These findings are discussed in the context of prenatal hormonal contributions to sexually dimorphic behavioral development both within and between the sexes. Recommendations for the conduct of future research in developmental behavioral endocrinology are presented.

High-Risk Sexual Behavior at a Midwestern University: A Confirmatory Survey

According to a 1991 study of sexual behavior based on a random sample of heterosexual undergraduates at a Midwestern university, 80% of the males and 73% of the females had experienced vaginal or anal intercourse. The average age at first vaginal intercourse was 17.2 years for both sexes. Seventeen percent of the sexually experienced males and 18% of the sexually experienced females had engaged in heterosexual anal intercourse; among these respondents, the average age at first anal intercourse was 20.3 for males and 19.1 for females. Although less than four years, on average, had elapsed since the respondents had first had vaginal intercourse, males reported an average of 8.0 lifetime vaginal-sex partners and females reported an average of 6.1. Overall, the findings from this random sample of students are similar to those from a 1988 convenience sample of the same college population.