Peer-adult offenders more consistently offended against females who were strangers or acquaintances, more frequently committed their crimes in a public area, and more often acted in a group with other offenders. Peer-adult offenders were also more likely to commit sex crimes in association with other criminal activities, and they evidenced higher overall levels of aggression and violence. In general, the aggression of child molesters tended to be intimidation rather than physical force, whereas the aggression of peer-adult offenders was more injurious and perhaps gratuitous. Violence in peer-adult offenders, but not in child molesters, was predicted by the interactive influence of victim gender, age, and level of resistance. 35 references and 3 tables