Minireview: Hormones and human sexual orientation

Area of Science:

• Neuroendocrinology
• Human Sexuality
• Developmental Biology

Background:

• Sexual orientation is commonly believed to be shaped by social factors.
• However, research indicates prenatal influences are critical for human sexuality.
• Sexual orientation is a sexually differentiated trait, similar to other characteristics influenced by early-life sex steroids.

Purpose of the Study:

• To investigate the role of prenatal factors, specifically sex steroids, in organizing human sexual orientation.
• To explore evidence linking prenatal endocrine conditions to variations in sexual orientation.
• To examine the interplay between biological and social factors in determining sexual orientation.

Main Methods:

• Comparative analysis of sexually differentiated traits in homosexual and heterosexual populations.
• Examination of clinical conditions with endocrine changes during embryonic development.
• Review of existing literature on prenatal hormone exposure and sexual orientation.

Main Results:

• Sexually differentiated traits differ between homosexual and heterosexual individuals, suggesting atypical prenatal endocrine exposure in homosexual subjects.
• Clinical conditions involving embryonic endocrine alterations show an increased incidence of homosexuality.
• Prenatal endocrine environment significantly influences sexual orientation, but a substantial portion of variance remains unexplained.

Conclusions:

• Prenatal endocrine factors, including sex steroids, are significant determinants of human sexual orientation.
• Genetic factors may also contribute directly or by modulating hormone action.
• The interaction between prenatal biological factors and postnatal social factors requires further investigation.