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Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia
Sarah Nila1, Pierre-Andre Crochet2, Julien Barthes3
1Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia.
Summary
Male homosexual preference (MHP) is partially feminized and linked to more older brothers in Indonesia. These findings suggest MHP
Area of Science:
- Evolutionary biology
- Human sexuality
- Psychology
Background:
- Male homosexual preference (MHP) presents an evolutionary puzzle due to heritability and fertility costs.
- Previous studies in Western societies noted feminization and the fraternal birth order (FBO) effect in homosexual men.
Purpose of the Study:
- To investigate the universality of feminization and the FBO effect in Indonesian male homosexual preference.
- To collect original data from homosexual men, heterosexual men, and heterosexual women in Java, Indonesia.
Main Methods:
- Facial photographs were analyzed to assess perceived feminization in homosexual men.
- Family data were collected to examine sibling composition and the FBO effect.
Main Results:
- Homosexual men's faces were perceived as feminized compared to heterosexual men.
- Homosexual men had a significantly higher number of older brothers, confirming the FBO effect in this population.
- Feminization in men was associated with having older brothers, irrespective of sexual orientation.
Conclusions:
- Male homosexual preference in Indonesia exhibits partial feminization and the FBO effect.
- These characteristics appear to be cross-culturally consistent with MHP in other regions.
- While feminization has evolutionary explanations, the FBO effect's mechanisms require further investigation.
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