Genetic and Environmental Influences on Female Sexual Orientation, Childhood Gender Typicality and Adult Gender Identity

Biological and Experimental Psychology Group, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.
PLoS ONE (Impact Factor: 3.23). 07/2011; 6(7):e21982. DOI: 10.1371/journal.pone.0021982
Source: PubMed


Human sexual orientation is influenced by genetic and non-shared environmental factors as are two important psychological correlates--childhood gender typicality (CGT) and adult gender identity (AGI). However, researchers have been unable to resolve the genetic and non-genetic components that contribute to the covariation between these traits, particularly in women.
Here we performed a multivariate genetic analysis in a large sample of British female twins (N = 4,426) who completed a questionnaire assessing sexual attraction, CGT and AGI. Univariate genetic models indicated modest genetic influences on sexual attraction (25%), AGI (11%) and CGT (31%). For the multivariate analyses, a common pathway model best fitted the data.
This indicated that a single latent variable influenced by a genetic component and common non-shared environmental component explained the association between the three traits but there was substantial measurement error. These findings highlight common developmental factors affecting differences in sexual orientation.

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    • "The finding that there were no significant differences in objective height between gynephilic, ambiphilic, and androphilic women does not support the current broader literature that suggests a biological basis to sexual orientation development in women. This does not, however, discount the body of research that suggests a biological basis for sexual orientation development in women (e.g.,Balthazart, 2011;Bao & Swaab, 2011;Brown et al., 2005;Burri, Cherkas, Spector, & Rahman, 2011;Hines, 2011;Langstrom, Rahman, Carlstrom, & Lichtenstein, 2010;LeVay, 2010;McFadden & Champlin, 2000;McFadden & Pasanen, 1998McFadden & Shubel, 2002;Ngun et al., 2011;Pearcey, Docherty, & Dabbs, 1996;Rahman, 2005;Singh et al., 1999). Given that this study has investigated only one physical factor that could be biologically related to sexual orientation development in women, our findings do not rule out the importance of other biological correlates in the development of women's sexual orientation (e.g., 2D:4D finger length ratios;Grimbos, Dawood, Burriss, Zucker, & Puts, 2010). "
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