Children who witness domestic violence are at an increased risk of having abusive relationships as adults, researchers have found.
If children witness abuse, they are more likely to be violent as adults
Being abused as a child and having behavioural problems also increases the risk of being violent as adults.
Receiving excessive punishment is another risk factor.
US researchers from Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute followed 540 children for 20 years from 1975.
They, and their mothers were interviewed in 1983, 1985 to 1986 and in 1991 to 1993.
They were then sent a questionnaire in 1999 on recent life changes, work history, aggressive behaviour and relationship history, including any violent relationships
If a pattern of violent behaviour towards a partner has been established, it is difficult to change say the researchers.
They say more needs to be done to develop prevention programmes that can help children before they reach adolescence.
Addressing behavioural problems in children may also help prevent them being violent as adults, the researchers said.
Breaking the cycle
If a child was hit by their parents, they were much more likely to see violence as a way of resolving problems as adults, the researchers found.
But seeing violence perpetuated between parents was found the be the greatest risk factor for being the victim of a violent partner as an adult.
Both men and women who witnessed domestic violence were likely to grow up to abuse their partners.
Miriam Ehrensaft, the psychologist who led the research, said once patterns of violent behaviour are established, they are very difficult to break, so families need help early in children's lives to break the cycle.
She said: "If families are targeted before children reach late childhood, patterns of excessive punishment may be prevented from becoming entrenched and later reproduced in adolescents' fledgling romantic relationships."
She added: "Punishment from mothers may serve as a model for physical expression of anger.
"This acceptance of coercive, power-based norms as ways of regulating conflict may have direct implications for young adults' means of conflict resolution with partners, independent of a disruptive behaviour disorder."
Professor Terrie Moffitt, of London's Institute of Psychiatry, has carried out research in the UK and New Zealand which came to similar conclusions.
She told BBC News Online: "This study's findings ought to change the focus of programmes to stop domestic violence.
"Today, we try to treat batterers, but not very successfully, and only after they have already injured their family members.
"Tomorrow, it should be possible to prevent domestic violence, by working with the aggressive youngsters who grow up to batter their partners."
Professor Moffitt added: "The study also shows that aggressive young girls become involved in violent domestic relationships.
"Many battered women's advocates will resist this information, because they prefer to think of women only as victims. But the evidence is clear that to stop domestic violence, we need to work with aggressive girls.
"If this study has one clear piece of advice for parents, it is never, ever hit each other in front of your children."
The research is published in the Journal of Consulting and Clinical Psychology.