The diverse historical, cultural, and physiological influences that determine sexual orientation are the focus of this fascinating work by one of the foremost investigators of human sexuality. Drawing on case studies from his sexology clinic, the author addresses the many enigmas of sexual orientation: What makes children grow up to be homosexual, heterosexual or bisexual? To what degree is gender determined before birth? What do we know about the relationship between hormones and homosexuality in adulthood? Also explored here is Money's pioneering concepts of lovemaps, the pathways of individual sexual and erotic development, and the factors that may shape overall healthy or pathological orientation, paraphilia, and gender transposition in childhood, adolescence, and maturity. Written in accessible language for researchers and clinicians, this authoritative work is both thought-provoking and informative as it explores timely questions of sexual orientation.