At one time it was believed that sex offenders could easily be categorized along three dimensions: offending against either adults or children, offending against either members or their families or against acquaintances and strangers, and offending in noncontact ways such as exhibitionism or through bodily contact. However, data increasingly indicate that some offenders offend across these categories. Many child sexual abusers are themselves adolescents, and many adult offenders first offended when they were adolescents. The literature reveals a paucity of controlled therapy outcome studies on the effectiveness of treatment. Existing uncontrolled studies are marked by methodological problems. This situation has led some to conclude that insufficient data exist to prove the effectiveness of treatment for child molesters. However, treatment programs have experienced major changes over the years, and some more recent studies provide reason for optimism about the effectiveness of current treatment methods for some offenders. Photograph and 101 reference notes (Author abstract modified)