H-Y Antigen and Homosexuality in Men

✍ Scribed by Ray Blanchard; Philip Klassen

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 148 KB
• Volume: 185
• Category: Article
• ISSN: 0022-5193
• DOI: 10.1006/jtbi.1996.0315

✦ Synopsis

In men, sexual orientation correlates with the number of older brothers, each additional older brother increasing the odds of homosexuality by approximately 33%. It is hypothesized that this fraternal birth order effect reflects the progressive immunization of some mothers to Y-linked minor histocompatibility antigens (H-Y antigen) by each succeeding male fetus, and the concomitantly increasing effects of H-Y antibodies on the sexual differentiation of the brain in each succeeding male fetus. This hypothesis is consistent with a variety of evidence, including the apparent irrelevance of older sisters to the sexual orientation of later-born males, the probable involvement of H-Y antigen in the development of sex-typical traits, and the detrimental effects of immunization of female mice to H-Y antigen on the reproductive performance of subsequent male offspring.