Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia
Male homosexual preference (MHP) is an evolutionary enigma because it is partially heritable and imposes a fertility cost. In occidental societies, homosexual men are feminized at various levels and they have more older brothers than heterosexual men. To evaluate whether femininity and the fraternal...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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SAGE Publishing
2019-11-01
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| Series: | Evolutionary Psychology |
| Online Access: | https://doi.org/10.1177/1474704919880701 |
| _version_ | 1818411753420095488 |
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| author | Sarah Nila Pierre-Andre Crochet Julien Barthes Puji Rianti Berry Juliandi Bambang Suryobroto Michel Raymond |
| author_facet | Sarah Nila Pierre-Andre Crochet Julien Barthes Puji Rianti Berry Juliandi Bambang Suryobroto Michel Raymond |
| author_sort | Sarah Nila |
| collection | DOAJ |
| description | Male homosexual preference (MHP) is an evolutionary enigma because it is partially heritable and imposes a fertility cost. In occidental societies, homosexual men are feminized at various levels and they have more older brothers than heterosexual men. To evaluate whether femininity and the fraternal birth order (FBO) effect are universal features of MHP or not, we collected original data from homosexual men, heterosexual men, and heterosexual women from Java (Indonesia). Facial photographs were used to test whether homosexual faces are feminized when compared with heterosexual ones. We found that faces manipulated to resemble the average face of homosexual men are perceived as facially feminized, suggesting that homosexual men are facially feminized compared to heterosexual men, although a higher facial femininity was not captured by morphological analyses. Then, family data were used to detect differences in siblings’ composition between homosexuals and heterosexuals. Homosexual men displayed a higher number of older brothers than heterosexual men, even when sibship size was controlled for, suggesting that the FBO effect exists in Indonesian populations. Independent of sexual orientation, men with older brothers seem more feminized than those without older brothers, consistent with the immune origin of the FBO effect. In conclusion, MHP in Indonesia is partially feminized and they have more older brothers. Such features are also associated with MHP in other cultural contexts, suggesting a cross-cultural effect of men homosexual preference. An evolutionary explanation is available for the feminizing effect, although the FBO effect remains unexplained even if proximal mechanisms start to be identified. |
| first_indexed | 2024-12-14T10:36:25Z |
| format | Article |
| id | doaj.art-6df5b745ac884df09fabc6f13d801583 |
| institution | Directory Open Access Journal |
| issn | 1474-7049 |
| language | English |
| last_indexed | 2024-12-14T10:36:25Z |
| publishDate | 2019-11-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | Evolutionary Psychology |
| spelling | doaj.art-6df5b745ac884df09fabc6f13d8015832022-12-21T23:05:55ZengSAGE PublishingEvolutionary Psychology1474-70492019-11-011710.1177/1474704919880701Male Homosexual Preference: Femininity and the Older Brother Effect in IndonesiaSarah Nila0Pierre-Andre Crochet1Julien Barthes2Puji Rianti3Berry Juliandi4Bambang Suryobroto5Michel Raymond6 Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia CEFE, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, France ISEM, Université de Montpellier, CNRS, IRD, EPHE, France Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University (Bogor Agricultural University), Indonesia ISEM, Université de Montpellier, CNRS, IRD, EPHE, FranceMale homosexual preference (MHP) is an evolutionary enigma because it is partially heritable and imposes a fertility cost. In occidental societies, homosexual men are feminized at various levels and they have more older brothers than heterosexual men. To evaluate whether femininity and the fraternal birth order (FBO) effect are universal features of MHP or not, we collected original data from homosexual men, heterosexual men, and heterosexual women from Java (Indonesia). Facial photographs were used to test whether homosexual faces are feminized when compared with heterosexual ones. We found that faces manipulated to resemble the average face of homosexual men are perceived as facially feminized, suggesting that homosexual men are facially feminized compared to heterosexual men, although a higher facial femininity was not captured by morphological analyses. Then, family data were used to detect differences in siblings’ composition between homosexuals and heterosexuals. Homosexual men displayed a higher number of older brothers than heterosexual men, even when sibship size was controlled for, suggesting that the FBO effect exists in Indonesian populations. Independent of sexual orientation, men with older brothers seem more feminized than those without older brothers, consistent with the immune origin of the FBO effect. In conclusion, MHP in Indonesia is partially feminized and they have more older brothers. Such features are also associated with MHP in other cultural contexts, suggesting a cross-cultural effect of men homosexual preference. An evolutionary explanation is available for the feminizing effect, although the FBO effect remains unexplained even if proximal mechanisms start to be identified.https://doi.org/10.1177/1474704919880701 |
| spellingShingle | Sarah Nila Pierre-Andre Crochet Julien Barthes Puji Rianti Berry Juliandi Bambang Suryobroto Michel Raymond Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia Evolutionary Psychology |
| title | Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia |
| title_full | Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia |
| title_fullStr | Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia |
| title_full_unstemmed | Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia |
| title_short | Male Homosexual Preference: Femininity and the Older Brother Effect in Indonesia |
| title_sort | male homosexual preference femininity and the older brother effect in indonesia |
| url | https://doi.org/10.1177/1474704919880701 |
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