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Evidence for Perinatal Steroid Influence on Human Sexual Orientation and Gendered Behavior
Ashlyn Swift-Gallant1, Talia Shirazi2, David A Puts2
1Department of Psychology, Memorial University of Newfoundland, St. John's A1B 3X9, Newfoundland and Labrador.
Prenatal hormone exposure, particularly androgens, influences human sexual orientation and gender conformity. Studies on finger length ratios and hormone deficiencies suggest early hormonal environments shape adult behaviors and preferences.
Area of Science:
- Endocrinology
- Neuroscience
- Psychology
Background:
- Perinatal exposure to gonadal steroid hormones can permanently affect behaviors in animals.
- Evidence suggests prenatal hormone levels influence adult human psychology, behavior, sexual orientation, and gender nonconformity.
Purpose of the Study:
- To investigate the influence of perinatal hormone levels on human sexual orientation and gender conformity.
- To explore the relationship between prenatal androgen exposure and sexual preferences.
Main Methods:
- Analysis of digit ratios (2D:4D) as an indicator of prenatal androgen exposure.
- Study of individuals with isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD).
- Correlation of digit ratios with recalled childhood gender nonconformity (CGN) and sexual role preferences.
Main Results:
- Lesbians, on average, show more masculine digit ratios than straight women, suggesting higher prenatal androgen exposure.
- Digit ratios do not differ between gay and straight men, but insertive gay men have more masculine ratios than receptive gay men.
- Men with IGD exhibit greater CGN, while women with IGD report less androphilia and more bisexuality compared to controls.
Conclusions:
- Perinatal androgen exposure appears to influence sexual orientation and gender conformity in humans.
- Early hormonal milieu, including ovarian steroids in females, plays a role in shaping adult sexual preferences and behaviors.
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