In discussing normative sexual behaviors at various developmental stages (0-5 years, 6-10 years, 10-12 years, and 13-18 years), the chapter examines behaviors in touching oneself, looking at others in stages of undress, and touching others. The chapter notes that acting-out or dysfunctional behaviors may be symptoms of sexual victimization in children but are not direct indicators. Three direct behavioral indicators of child sexual abuse, however, include excessive masturbation, promiscuity, and the sexual abuse of another person. A methodology of assessing sexually abusive behavior by children is presented. It involves the complaint status (has a complaint of sexual abuse been made), behavioral indicators of sexual abuse, compliance with developmental norms for sexual behavior, the relative power positions of participants, the use of force or intimidation, ritualistic or sadistic behaviors, and secrecy. 8 references.