This article summarizes recent studies examining differences in neuropsychological profiles between homosexual and heterosexual men and women. Some studies have found differences in cognitive patterns between gay men and heterosexual men on measures of typical sex differences, but two studies found no effects of sexual orientation. Little is known about differences between lesbians and heterosexual women, as the few published reports found no significant differences. The studies aim to understand the etiology of sexual orientation by examining neurocognitive development in the direction of one's opposite sex. Prenatal hormone theory suggests high concentrations of androgenic hormones during brain development masculinize neural substrates related to sexual orientation and cognition.

1. • A Neuropsychologic Profile of Homosexual and Heterosexual Men and Women
• Journal article by Domonick J. Wegesin; Archives of Sexual Behavior, Vol. 27, 1998
A neuropsychologic profile of homosexual and heterosexual men and
women.
by Domonick J. Wegesin
INTRODUCTION
Recent neuropsychologic studies have been employed as a means of understanding the
etiology of sexual orientation. This approach supplements neuroanatomic and
neurophysiologic approaches which have examined differences in brain structure and
brain function between homosexual (HM) and heterosexual (HT) individuals (e.g.,
LeVay, 1991; Reite et al., 1995). Some of the neuropsychologic data suggest that the
cognitive patterns of gay men differ from those of HT men on measures that generally
elicit sex differences (Gladue et al., 1990; McCormick and Witelson, 1991; Sanders and
Ross-Field, 1986). However, at least two studies have failed to reveal effects of sexual
orientation (Gladue and Bailey, 1995; Tuttle and Pillard, 1991). Little is known about
cognitive abilities of lesbians, though the four published reports suggest that lesbians do
not differ significantly from HT women. (Gladue and Bailey, 1995; Gladue et al., 1990;
Hall and Kimura, 1993; Tuttle and Pillard, 1991).
Theoretically, this body of data has been generated in the framework of psychosexual
differentiation, i.e., the development of physical and behavioral differences between the
sexes. Homosexuals are thought to follow sex-atypical patterns of psychosexual
differentiation such that they develop neurocognitively in the direction of their opposite-
sex HT cohorts. This hypothesis is supported by studies of gender-role behavior which
indicate that gay men and lesbians are much more likely to report sex-atypical histories
of childhood behavior than HT men and women (d = 1.31 for men, d = 0.96 for women;
Bailey and Zucker, 1995). The most prominent theory accounting for the relation
between homosexuality and sex-atypical cognitive abilities implicates the role of
prenatal sex hormones (Meyer-Bahlburg, 1993).
Prenatal hormone theory suggests that high concentrations of androgenic hormones are
required during the period of sexual differentiation of the brain to masculinize the
neural substrates relevant to sexual orientation and neurocognitive function. Without the