Evidence against a Relationship between Dermatoglyphic Asymmetry and Male Sexual Orientation

Abstract

Hall and Kimura (1994) studied the relation between dermatoglyphic asymmetry and male sexual orientation in a sample of 66 homosexual and 182 heterosexual men. They found that more homosexual men possessed a leftward dermatoglyphic asymmetry than did heterosexual men. In this paper, we report a comparative study about the relationship between sexual orientation and dermatoglyphic characteristics, including 60 homosexual men, 76 heterosexual men, and 60 heterosexual women, recruited from the general population, and also from a gay-rights nongovernmental organization, in Salvador, Brazil. Ulnar loops were the most frequent dermatoglyphic pattern in all groups, followed by whorls, arches, and radial loops. A chisquare analysis comparing the frequencies of the patterns in the three groups only showed an excess of ulnar loops in women ( p < 0.05) and arches in men (p < 0.01), but did not reveal significant differences between homosexuals and the other groups studied. There was no significant difference between gay and straight men on total ridge count. We found a preponderance of rightward asymmetry in homosexual and heterosexual men, as well as in heterosexual women. Our results do not agree with Hall and Kimura's data indicating that more gay men possessed the minority leftward asymmetry than did straight men. There was no significant difference in leftward asymmetry in the sample studied. The results reported in this paper do not support any relation between dermatoglyphic asymmetry and male sexual orientation, and, thus, any hypothesis concerning a biological intrauterine contribution to adult sexual orientation somehow associated with dermatoglyphic development.Since the middle of the 19th century, the etiology of sexual orientation has been the subject of an enduring controversy. For a long time, the debate on this issue has been marked by a conflict between the extremes of biological and environmental determinism: was sexual orientation determined by the biology of the in-

No association between two candidate markers of prenatal sex hormones: Digit ratios (2D:4D and other) and finger‐ridge counts

“…However, data from several other recent reports congruently suggest that this sex effect might indeed be quite small. For example, based on 60 male and 60 female Brazilian heterosexual adults (Forastieri et al, 2002;calculated from their For the sake of completeness as well as for comparative purposes, the present study in addition followed the dataanalytic approach of the two prior related studies (Daly et al, 2008;Manning, 2002), that is, combined-sex analyses were also conducted. These supplemental tests likewise yielded no reliably and consistently negative associations between the 2D:4D ratio and finger-ridge counts.…”

“…However, data from several other recent reports congruently suggest that this sex effect might indeed be quite small. For example, based on 60 male and 60 female Brazilian heterosexual adults (Forastieri et al, 2002;calculated from their Kimura and Carson (1995) observed a sex effect for TFRC of d ¼ .37 in their sample of 154 male and 96 female Canadian undergraduates.…”

Prenatal sex hormone effects on child and adult sex-typed behavior: methods and findings

“…Sexual orientation. In men, fingerprint asymmetry was found to be associated with sexual orientation in one study, with homosexual men found to have the femaletypical LOR pattern more often than heterosexual men [272], but this was not replicated in two studies of homosexual men [273,274] or in two studies of transsexual men [275,276]. In women, fingerprint asymmetry has not been found to relate to sexual orientation, with two studies failing to find differences between homosexual and heterosexual women [234,274].…”

Fluctuating Asymmetry and Sexual Orientation in Men and Women

“…If sexual orientation is influenced by prenatal perturbations, then people expressingahomosexualphenotypeshouldalsoshowmarkers of elevated DI (i.e., increased left handedness and greater levels of FA). Previous studies using dermatoglyphic asymmetry and somatic asymmetry of the hands (finger length) have revealed null results (Forastieri et al, 2002;Mustanski et al, 2002a). This may suggest that the time period in which digits develop prenatally may not coincide well with a critical period for brain development related to sexual orientation.…”