A study suggests that distinct biological mechanisms can influence sexual orientation in men. Various biomarkers are associated with male sexual orientation, suggesting possible underlying immunological, endocrine, and genetic mechanisms. However, the biomarkers have been studied in isolation, and the extent to which they overlap or interact remains unclear. Ashlyn Swift-Gallant and colleagues used a method called latent profile analysis to examine the distribution of three established biomarkers of sexual orientation--number of older brothers, left-handedness, and familiality of same-sex orientation--in more than 800 men, 18 years of age and older. The analysis identified four subpopulations within the sample, which could be distinguished based on the biomarkers. None of the biomarkers were elevated among men in the first subgroup, whereas each of the remaining subgroups exhibited elevated levels for only one of the biomarkers. The biomarker that was elevated differed for each subgroup. The three subgroups with elevated biomarker levels each had a higher proportion of nonheterosexual men compared with the subgroup that did not exhibit any elevated biomarker levels. The four subgroups differed significantly with respect to measures of gender nonconformity and personality traits such as femininity and agreeableness. The results suggest the existence of subgroups of nonheterosexual men whose sexual orientation may be associated with different biological mechanisms, according to the authors.
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Article #18-09920: "Evidence for distinct biodevelopmental influences on male sexual orientation," by Ashlyn Swift-Gallant, Lindsay A. Coome, Madison Aitken, D. Ashley Monks, and Doug P. VanderLaan.
MEDIA CONTACT: Ashlyn Swift-Gallant, Memorial University of Newfoundland, St. John's, CANADA; tel: 709-864-7583; e-mail: <aswiftgallant@mun.ca>; Doug VanderLaan, University of Toronto Mississauga, CANADA; tel: 905-569-5782; email: <doug.vanderlaan@utoronto.ca>
Journal
Proceedings of the National Academy of Sciences