Brief structured clinical interview data and institutional history up to age 18 were examined and coded. Four factors were derived from principal components analysis, and multiple regression analyses were performed with two noteworthy results. First, distinct aspects of developmental history were related to sexual and non-sexual aggression in adulthood. Associated with the severity of sexual aggression were caregiver inconstancy and sexual deviation in the family. Related to the severity of non-sexual aggression were childhood and juvenile institutional history and physical abuse and neglect. Second, the severity of aggression rather than the frequency of crimes was predicted by developmental history, a finding contrary to previous studies of criminal populations. 7 tables, 74 references. (Author abstract modified)