The assessment and treatment of children and adolescents who engage in sexually abusive behavior requires an understanding of normal sexual development. A multiplicity of biological and psychosocial factors determines the child's sexual development, gender role, sexual orientation, patterns of sexual arousal, sexual cognitions, sexual socialization, and the integration of sexual and aggressive patterns of behavior. The individual's sexuality evolves in concert and as a result of interaction with family, ethnic, social, and cultural influences. The practice parameters presented in this article summarize what is known about the epidemiology and phenomenology of sexually abusive youths and provide guidelines for the assessment and the selection of treatment interventions for these youths. Essential considerations in the assessment and treatment of sexually abusive youths, as well as the various categories of sexually abusive youths that should be recognized and that influence treatment decisions, are presented. The spectrum of currently available psychosocial and biological treatments is profiled. 2 tables and 174 references