BY ANY objective measure, comedian Billy Connolly is a towering success. Yet as a child he was sexually abused. Samantha Morton, Tom Cruise鈥檚 co-star in the film Minority Report, also suffered as a child, neglected after the messy break-up of her parents鈥� marriage and consigned to a series of children鈥檚 homes. But like Connolly she has turned out just fine.
What makes some maltreated kids triumph over their early problems while others turn antisocial or violent? A supportive school, caring friends, perhaps the right social worker or a loving relative 鈥� any or all of these may ride to the rescue in particular cases. But if you鈥檙e looking for a more reliable factor, try a brain enzyme called monoamine oxidase.
At least, that鈥檚 the message of a remarkable genetic study published last week in the journal Science(Vol 297, p 851). The research suggests that people endowed with an abundance of the enzyme are more likely to tough-out an unhappy or abusive childhood and lead a normal adult life than those born with lacklustre levels. And by no small margin: male victims of child abuse in the study were nine times as likely to turn thuggish and mean themselves if they were born with a sluggish version of the gene for the enzyme instead of a more active one.
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So opens another chapter in the long-running and often rancorous debate about genes and criminality. Even before last week鈥檚 study was published, theologians and ethicists were press-releasing their concerns about its implications for our understanding of free will and moral responsibility, with one religious commentator, bizarrely, appearing to link the gene to original sin. Many critics will look at the study and think it proves only that science is still in thrall to its eugenics past, determined to put genetic makeup at the centre of complex social issues where it has no place. Others will think just the opposite 鈥� that science has at last proved there really is a gene for violence, and that a piece of wayward DNA is the real culprit for the psychological damage wrought by child abuse. Neither view makes any sense.
Until now, most research in this area simply looked at violent people or criminals and asked what was different about their biology, be it chromosomes, hormones or, in the 19th century, sloping foreheads. But of course our personalities are never going to be shaped entirely by genes when so much of who we are comes from mother nurture.
The new study is more sophisticated. It looks at nature and nurture together and asks whether the two might combine disastrously in some people and families to create cycles of violent behaviour 鈥� and claims the answer is an emphatic yes. While boys carrying the sluggish version of the gene were no more likely than others to go off the rails if their childhood was untroubled, a staggering 85 per cent turned into antisocial adults if their childhood was troubled.
This research is an improvement on old-style eugenics, but where does it take us? Nowhere, until a second team replicates the findings in a separate population. But let鈥檚 assume these researchers have hit on something. There can be no doubt that if it鈥檚 confirmed, this genetic link will help to explain why some children end up more damaged than others by childhood maltreatment. It might even throw light on why violence and antisocial behaviour are more common in men than women. The gene for the enzyme is on the X chromosome, so while boys must make do with a measly single copy, girls enjoy the luxury of always inheriting two.
Yet, being true doesn鈥檛 make a scientific explanation useful in practical terms. For example, the study seems to raise the prospect of the authorities one day genetically screening boys so they can offer extra support 鈥� perhaps a drug 鈥� to those with the sluggish gene. This is a non-starter. First you鈥檇 have to be sure that interfering with the enzyme didn鈥檛 affect other aspects of a child鈥檚 personality (it probably would). Even then this approach would be doomed. One in three males carries this sluggish gene. Even if you could medicate them all, you鈥檇 be fixing something that isn鈥檛 really broken. These boys are not victims of a toxic brain chemistry. They are victims of a toxic childhood. Take away the latter and you don鈥檛 have a problem.
In fact, any attempt to base social policy on this science would not just be impractical. It could be dangerous, fuelling complacency about those with the active gene. Monoamine oxidase is not like some sort of Star Trek force field, offering complete protection against all forms of wickedness. Plenty of boys with the active gene in the study became antisocial adults. And you don鈥檛 have to be a thug to be unhappy and unfulfilled. Were the kids who didn鈥檛 turn violent as content in life as they might have been? We can never know.
No doubt the finding will encourage lawyers to invoke the 鈥済enetic defence鈥�. But judges should be cautious of this: there鈥檚 no evidence that the gene wipes out a person鈥檚 sense of right and wrong.
Child abuse and neglect are always wrong and always to be rooted out. It does not become any less wicked or deserving of vigilance because the victim has a gene that protects them from some of the consequences.