The subjects were mostly recidivists, men who either had previous records of sexual assault or who admitted to similar prior offenses for which they had not been caught. Of these subjects, 170 had sexually assaulted adult victims, while 178 had victimized children. Data pertaining to sexual trauma in the life histories of these men were retrieved through interviews with subjects and/or a study of their clinical records. A comparison group of 62 male law enforcement officers was administered an anonymous questionnaire regarding sexual trauma witnessed or experienced in childhood that was emotionally upsetting or disturbing. Evidence of some form of sexual trauma during their developmental years (ages 1 through 15) was found in the life histories of 31 percent of the offenders, while only 3 percent of the control group reported similar experiences. The predominant type of trauma experienced by child molesters was a forcible sexual assault, whereas for rapists the abuse had taken the form of being pressured into sexual activity by an adult. Other traumatic events reported by the offenders included 19 cases of sex-stress situations connected with family anxiety over the subject's involvement with sexual activity, 12 cases of witnessing upsetting sexual activity and 8 cases of some sexual injury or physiological handicap. In 50 instances, subjects victimized by members of their own family, and the majority became victims in their preadolescent years. Incidences of sexual assault perpetrated by adult women against children appear far higher than that reflected by official crime statistics. It is suggested that forcible, repetitive sexual assault can be understood to be a result more of internal, psychological determinants in the offender than external, situational determinants in his environment. In many cases the sexual assaults appear to replicate the offender's own victimization. Four references are provided.