title: Genetic and environmental influences on female sexual orientation, childhood gender typicality and adult gender identity.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Biological and Experimental Psychology Group, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom. a.burri@qmul.ac.uk
authors.forename: Andrea
authors.initials: A
authors.lastname: Burri
authors.forename: Lynn
authors.initials: L
authors.lastname: Cherkas
authors.forename: Timothy
authors.initials: T
authors.lastname: Spector
authors.forename: Qazi
authors.initials: Q
authors.lastname: Rahman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003710:Demography; D004777:Environment; D005260:Female; D005783:Gender Identity; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015999:Multivariate Analysis; D010641:Phenotype; D012725:Sexual Behavior; D014427:Twins / Q000235:genetics*; D055815:Young Adult