The effects of facial symmetry and sexually-dimorphic facial proportions on assessments of sexual orientation.

This study examined how perceptions of a person’s sexual orientation may be influenced by facial bilateral symmetry and sexually-dimorphic facial proportions thought to be influenced by sex hormones. Pictures of individuals who self-identified their sexual orientation were measured for facial symmetry and certain facial proportions. Independent raters were asked to identify the sexual orientation of those in the pictures on a continuum scale. Self-identified heterosexuals had facial measures that were less asymmetrical than homosexuals. The more likely raters perceived someone to hold a heterosexual orientation, the more symmetrical that person’s facial features were. There were few differences seen for the individual, sexually-dimorphic trait measurements between self-identified heterosexual and homosexual individuals; however, an examination of a composite of traits showed that heterosexual men had greater overall masculine facial features than did gay men. Furthermore, the more masculine a male’s overall facial features were, the more likely he was perceived as being heterosexual. These findings suggest that individuals may be using cues of facial symmetry and male facial masculinity to judge one’s sexual orientation.