Book excerpt: This book presents leading experts on the scientific study of gender, providing their views on what we know today about the relationship between gender nonconformity in childhood and future adult sexual identities or behaviors. This book explores the topic from a wide range of perspectives, including historical, sociological, psychological (social and developmental), and psychiatric viewpoints. Parents, parent educators, therapists, and counselors who work with gay, lesbian, and bisexual adolescents or adults and/or gender atypical children will find this resource insightful and very useful. It presents highly respected authorities offering their own expertise and perspectives on a subject of much cultural controversy. Chapters explore: historical and cultural examples which suggest that homoerotic relationships during adolescence or early adulthood do not necessarily lead to homosexuality; the difficulty in identifying an example of a pattern of childhood behaviors that is predictive of outcome; a review of empirical retrospective and prospective literature; whether there is a causal link between childhood gender nonconformity and sexual orientation; and the diagnostic category of Gender Identity Disorder in the most recent DSM. This book was published as a special issue of the Journal of Gay & Lesbian Mental Health.