Genetic factors predisposing to homosexuality may increase mating success in heterosexuals

Zietsch, Brendan P., Morley, Katherine I., Shekar, Sri N., Verweij, Karin J. H., Keller, Matthew C., Macgregor, Stuart, Wright, Margaret J., Bailey, J. Michael and Martin, Nicholas G. (2008) Genetic factors predisposing to homosexuality may increase mating success in heterosexuals. Evolution and Human Behavior, 29 6: 424-433. doi:10.1016/j.evolhumbehav.2009.07.002


Author Zietsch, Brendan P.
Morley, Katherine I.
Shekar, Sri N.
Verweij, Karin J. H.
Keller, Matthew C.
Macgregor, Stuart
Wright, Margaret J.
Bailey, J. Michael
Martin, Nicholas G.
Title Genetic factors predisposing to homosexuality may increase mating success in heterosexuals
Journal name Evolution and Human Behavior   Check publisher's open access policy
ISSN 1090-5138
Publication date 2008-11
Year available 2008
Sub-type Article (original research)
DOI 10.1016/j.evolhumbehav.2009.07.002
Open Access Status
Volume 29
Issue 6
Start page 424
End page 433
Total pages 10
Place of publication New York, NY, U.S.A.
Publisher Elsevier Science
Language eng
Subject 1701 Psychology
Abstract There is considerable evidence that human sexual orientation is genetically influenced, so it is not known how homosexuality, which tends to lower reproductive success, is maintained in the population at a relatively high frequency. One hypothesis proposes that while genes predisposing to homosexuality reduce homosexuals' reproductive success, they may confer some advantage in heterosexuals who carry them. However, it is not clear what such an advantage may be. To investigate this, we examine a data set where a large community-based twin sample (N=4904) anonymously completed a detailed questionnaire examining sexual behaviors and attitudes. We show that psychologically masculine females and feminine men are (a) more likely to be nonheterosexual but (b), when heterosexual, have more opposite-sex sexual partners. With statistical modelling of the twin data, we show that both these relationships are partly due to pleiotropic genetic influences common to each trait. We also find a trend for heterosexuals with a nonheterosexual twin to have more opposite-sex partners than do heterosexual twin pairs. Taken together, these results suggest that genes predisposing to homosexuality may confer a mating advantage in heterosexuals, which could help explain the evolution and maintenance of homosexuality in the population.
Keyword Homosexuality
Sexual orientation
Genetic; Environmental
Mating success
Evolution
Antagonistic pleiotropy
Darwinian paradox
Heritability
Gender identity
Masculinity
Femininity
Q-Index Code C1
Q-Index Status Provisional Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Psychology Publications
 
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Created: Thu, 25 Feb 2010, 14:55:29 EST by Mr Brendan Zietsch on behalf of School of Psychology