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 masculinizing effects of androgenic hormones, a female-typed neural substrate
results. Nonhuman animal studies provide evidence consistent with this theory.
Prenatal manipulations of androgens during critical periods can induce sex-atypical
reproductive and nonreproductive behaviors (Beatty, 1992; Gorski, 1985). Prenatal
hormone manipulations are also associated with the development of sex-specific
neural dimorphism (Breedlove, 1994). Further, human studies of psychoendocrine
populations suggest that prenatal sex hormones are important in the development of
sexual orientation. Sex atypicalities in prenatal hormone level have been correlated
with increased bi- and homosexuality in these populations (Dittmann et al., 1992;
Ehrhardt et al., 1985; Money et al., 1984). Of relevance to the current report are data
suggesting that prenatal hormones are also related to sexually dimorphic cognitive