Sex Hormones and Sexual Behavior

Abstract

In certain animals the effects of gonadal steroids on sexual behavior are mediated directly by the central nervous system: however, in humans the degree to which sexual identity or sexual role behavior is directly determined by endocrine function is unclear. Furthermore, the relative importance of hormonal versus psychiatric, social, and cultural factors as determinents of sexual identify is in dispute. The findings of Imperato-McGinley and her associates, published in this issue, tend to support the theory that hormonal factors are of primary importance in determining male sexual identity. Patients with a deficiency of steroid 5alpha-reductase have decreased digydrotestosterone production during fetal development, and are thus born with female-like external genital organs. Generally they are raised as females but during childhood and puberty normal testerone activity takes place; therefore, at puberty the majority of these individuals assume a male identity. This identity change was attributed to androgen activity. Studies of this nature contribute to our understanding of the role of hormones; however, it must be kept in mind that the study provides only circumstantial evidence and that the findings do not rule out the possible influence of psychological, social, or cultural factors on sexual role behavior. For example, male pseudohermaphradites are frequently born with clitoromegaly, and during childhood this may introduce feelings of uncertainty as to sexual identity. Nor is it clear that the change to male identity is the result of the direct effect of testosterone on the central nervous system; the enlargement of accessory male organs at puberty may itself influence sexual role behavior.