A study says a genetic factor may explain why some men who were abused as children mature into violent criminals.
The study followed 442 males in New Zealand for 26 years.
Men who were abused and had a flawed brain chemical gene were far more likely to commit criminal or anti-social actions.
Abuse victims with low gene activity had 44 percent of violent crime convictions, although they were only 12 percent of the study group.
Abuse victims with normal genes were no more likely to be anti-social than those who were not abused. Experts say the finding could lead to new ways of helping abused children become responsible adults.
A study co-author is a psychologist at the University of Wisconsin-Madison. The study is in the journal Science.