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Developmental theories of the biological basis of sexual orientation suggest that sexually differentiated psychological and behavioural traits should be linked with sexual orientation. Subgroups of gay men delineated by anal sex roles differ according to at least one such trait: gender expression.
The present study assessed the hypothesis that handedness, a biologically determined sexually differentiated trait, corresponds to differences in subgroups of gay men based on anal sex role. Furthermore, it assessed whether handedness mediates the association between gender nonconformity and male sexual orientation.
Gay men also completed measures of anal sex role preference. As in previous studies, gay men showed greater non-right-handedness and gender nonconformity than straight men. Together, these findings suggest that developmental processes linked to handedness underpin variation among men in sexual orientation and gender nonconformity as well as variation among subgroups of gay men that are delineated by anal sex roles.
Handedness, or predominantly using the left or right hand for various tasks, is a marker of cerebral lateralization for review, see [ 1 ]. Extensive research suggests that handedness is influenced by genetic factors and is also linked to sexually dimorphic endocrine and immunological mechanisms [ 2 — 5 ]. Although the factors affecting handedness are still under investigation, there is consensus that it is determined prenatally by biological factors for review, see [ 6 ].
