The subjects included 4,269 consecutive live males born in Denmark on whom measures of birth complications (forceps extraction, breech delivery, umbilical cord prolapse, preeclampsia, and long birth duration), early maternal rejection at age 1 year (related to home condition, marital status, and out-of-home placements for the infant), and violent crime at age 18 years, were collected. There was a significant interaction between birth complications and early maternal rejection indicating that these children were most likely to become violent offenders in adulthood. While only 4.5 percent of the cohort displayed both risk factors, this group accounted for 18 percent of all violent crimes committed by the group as a whole. This effect was not observed in relation to nonviolent offending. 1 figure and 37 references