@article {308688,
	title = {Genetic factors predisposing to homosexuality may increase mating success in heterosexuals},
	journal = {Evolution and Human Behavior},
	volume = {29},
	year = {2008},
	month = {11/2008},
	pages = {424-433},
	chapter = {424},
	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{\textquoteright} 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.},
	keywords = {Antagonistic pleiotropy, Darwinian paradox, Environmental, Evolution, Femininity, Gender identity, Genetic, Heritability, Homosexuality, Masculinity, Mating success, Sexual orientation},
	doi = {10.1016/j.evolhumbehav.2008.07.002},
	url = {https://www.sciencedirect.com/science/article/pii/S1090513808000688},
	author = {Zietsch, B. and Morley, K. and Shekar, S. and Verweij, K. and Keller, M. and Macgregor, S. and Wright, M. and Bailey, J. M. and Martin, N.}
}
