The results of a study linking avoidable birth complications to adult violence shows the importance of healthy and safe births in reducing the violent crime rate.
Psychologists who followed 4,269 males from birth to the age of 18 believe they have found the first hard evidence of an avoidable biological factor that increases the risk of a person becoming a violent criminal.
Professor Adrian Raine, a former Home Office psychologist now at the University of Southern California, Los Angeles, revealed details of the research at the annual meeting of the American Association for the Advancement of Science in San Francisco. 'It is indisputably the case that biological factors do predispose to violence. Furthermore, we are not talking about a trival predisposition. Biological factors do contribute to violence in a non-trivial way.'
He added: 'Birth complications predispose to adult criminal violence. These complications are things like breech birth, forceps delivery, bleeding.'
The study, carried out on randomly selected males born in Copenhagen between 1959 and 1961, found that the 3.4 per cent in the sample who suffered both birth complications and rejection by parents were responsible for 22 per cent of the violent crime in the group, such as murder, assault and rape. Parental rejection was defined by whether the mother had reported the pregnancy as unwanted, tried to have an abortion, or whether the baby did not live at home for at least four months in the first year of life.
Birth complication or parental rejection on their own did not lead to violent criminality. 'It is specifically the combination of the birth complications and parental rejection that leads to violence,' Professor Raine said.
'We found that birth complications combined with early parental rejection predisposes to violent offending 18 years later.
'It's a classic example of a biosocial interaction, a biological factor - birth complication - and a social factor - early parental rejection - that combine to produce a predisposition to violent behaviour.'
The researchers suspect that birth complications are leading to some mild degree of brain dysfunction in early life and 'further down the road that leads to IQ deficits, failure in school, unemployment and one can imagine how one can then fall into a criminal way of life. But that is speculation at the moment . . .', he said.