Dermatoglyphics, handedness, sex, and sexual orientation.

Both handedness and dermatoglyphic asymmetry reflect early, prenatal influences and both have been reported to be associated with male sexual orientation; handedness has been related to female sexual orientation as well. Neurohormonal and developmental perturbation are two competing hypothesis that attempt to explain these connections. We attempted to replicate these associations and to extend dermatoglyphic asymmetry findings to women. Dermatoglyphic directional asymmetry and fluctuating asymmetry were unrelated to sexual orientation. Homosexual women, but not homosexual men, had highly significant increases in non-right-handedness compared with same-sex heterosexual controls. Although this pattern of results does not allow resolution of the two competing models, it does lend additional support to a biological basis of sexual orientation.