Second, clinical conditions associated with significant endocrine changes during embryonic life often result in an increased incidence of homosexuality. Because some of these traits are known to be organized by prenatal steroids, including testosterone, these differences suggest that homosexual subjects were, on average, exposed to atypical endocrine conditions during development. First, multiple sexually differentiated behavioral, physiological, or even morphological traits are significantly different in homosexual and heterosexual populations. Two types of evidence support this notion. In animals and men, many sexually differentiated characteristics are organized during early life by sex steroids, and one can wonder whether the same mechanism also affects human sexual orientation. Sexual orientation is a sexually differentiated trait (over 90% of men are attracted to women and vice versa). There are, however, a large number of studies indicating that prenatal factors have an important influence on this critical feature of human sexuality.
heterosexuality) is determined by education and social constraints. Many people believe that sexual orientation (homosexuality vs.
