This article is a review and brief discussion of recently gathered information on androgens and sexual behavior in men. It includes experimental observations on the covariance between androgens, mainly testosterone, and sexual functioning in normal heterosexual men and studies on sexual dysfunction and homosexual behavior. The effects of castration, hypogonadal conditions, hormonal replacement, and endogenous testosterone variations on sexual behavior are examined. Further psychoendocrine studies are necessary to evaluate the role of gonadal hormone production in impotency. Current pharmacological research does not furnish specific evidence that the administration of androgens or preparations that stimulate the secretion of endogenous androgens have beneficial effects on functional impotence. After reviewing the studies on male homosexuality and androgen levels, the article concludes that it has not been established that homosexual men are characterized by abnormalities in plasma testosterone.