Biological Research on Women's Sexual Orientations: Evaluating the Scientific Evidence

Journal of Social Issues, Summer, 2000 by Rosemary C. Veniegas, Terri D. Conley

Eight English-language studies, including a total of 238 women, tested the predicted association between CAH and same-sex sexual behavior. Five studies reported some bisexual behavior among CAH women. Dittman et al. (1992) found that 20% of CAH women versus none of their non-CAH sisters had or wished to have "a relationship with a female partner." Ehrhardt et al. (1968) found that 17% of CAH women reported engaging in both heterosexual and homosexual behaviors. None reported only homosexual behavior. Ehrhardt (1979) found that 8% of the CAH women bad "bisexual love relationships." Money et al. (1984) reported that 17% of CAH women versus 4% of a control group had "homoerotic partner contact." Mulaikal, Migeon, and Rock (1987) reported that 5% of CAH women bad "homosexual or bisexual" sexual activity. However, note that only two of these studies included control groups and neither used a standardized measure of sexual orientation. Three studies reported no evidence of any homosexual behavior among CAH women ( Lev-Ran, 1974; Slijper et al., 1992; Zucker et al., 1996). The most rigorous study to date (Zucker et al., 1996) found that none of the CAH and control women reported same-sex sexual behavior such as dating or kissing. Researchers have failed to demonstrate that the majority of CAH women engage in predominantly or exclusively same-sex sexual behavior. Thus, most CAH women engage in heterosexual sexual behavior and have heterosexual relationships.

In summary, there is somewhat stronger evidence that CAH is associated with more same-sex sexual fantasy than that it is associated with more same-sex sexual behavior. The finding of greater same-sex fantasy among CAH women than among comparison women is consistent with the prenatal hormonal hypothesis. However, most CAH women were categorized as exclusively heterosexual in fantasy and behavior. In a recent review of the CAH research Pattatucci (1998, pp. 27-28) concluded, "These results suggest that excess prenatal androgens predispose some women to the development of same-gender sexual orientation. However, because CAH is a relatively rare condition, and a majority develop a heterosexual orientation, CAH plays a minor role in the overall variability of women's sexual orientation within the general population."

DES research. The prenatal hormonal hypothesis has also been investigated among women exposed to DES, a synthetic estrogen formerly prescribed to pregnant women who were at risk for having miscarriages. Use of DES halted in 1971 when it was found to be related to an increased risk of cancer in female offspring. In an early study Ehrhardt et al. (1985) reported greater "bisexual or homosexual responsiveness" (a combined measure of fantasy and sexual relations) among 30 DES-exposed women compared with 42 unexposed control women. The majority (75%) of DES-exposed women were categorized as exclusively or nearly exclusively heterosexual over their lifetime. A more recent study compared 97 DES-exposed women with 117 unexposed control women (Meyer-B ahlburg et al., 1995). Participants were interviewed about their sexual fantasies and sexual relations during the prior year and since puberty. Their responses were rated using Kinsey scale scores. Twelve possible comparisons between DES-exposed women and unexposed cont rol women in overall fantasy and sexual relations were tested. Two statistically significant differences (p [less than] .05) between DES women and control women were found. During the prior year, 31% of DES-exposed women versus 7% of control women reported having same-sex fantasies. Since puberty 17% of DES-exposed women versus 0% of control women had had same-sex sexual relations. Note, however, that the majority of DES-exposed women were categorized as heterosexual in fantasy and behavior across time periods. Only 4 of the DES-exposed women were categorized as exclusively homosexual in sexual responsiveness since puberty compared with none of the control women. Meyer-Bahlburg et al. (1995, p. 17) concluded, "The extent to which bisexuality and homosexuality were increased in DES women was rather modest...differences between DES and control women were limited to degrees of bisexuality...confined to imagery and was not expressed in actual sex with partners." In summary, experts on this topic believe that DES exposure has only modest effects on sexual orientation, and that these effects are associated with bisexuality rather than homosexuality among some women.