July 28, 2008 in Nation/World

Researchers link genes to criminal tendencies

By Zoe Elizabeth Buck McClatchy

Controversial concept

In 1927 the U.S. Supreme Court ruled in favor of forced sterilization of the mentally ill and dangerous criminals. In defense of the decision, Justice Oliver Wendell Holmes wrote: “It is better for all the world if instead of waiting to execute degenerate offspring for their crime … society can prevent those persons who are manifestly unfit from continuing their kind.” The practice continued until 1942 when the court ruled it unconstitutional.

RALEIGH, N.C. – Maybe some boys really were born to be wild.

Researchers at UNC Chapel Hill announced this week that they had found three genes that appear to affect the probability of a life of crime.

The study looked at roughly 1,100 boys ages 12-18.

In 1996 and again in 2002, the participants were asked to take a 12-question survey to gauge their delinquent tendencies. The participants’ delinquency scores were matched against their genetics to look for a correlation.

The results clearly showed a genetic basis for aggressive behavior.

The idea that personality and behavior can be predicted by genetics is not a new one, and it has a dark past. “Bad genes” were the basis in the 19th century for Henry Goddard’s theory of eugenics, which was used as a justification for racial supremacy.

In the current research, scientists emphasized that having the gene doesn’t necessarily mean a child is destined to become a criminal.

“It’s not like with some genetic diseases, like cystic fibrosis or Huntington’s, where when you have the genes the likelihood increases by 5,000 fold,” said Guang Guo, a professor of sociology at UNC-CH and the study’s lead author. “If you have the genotype you’re not necessarily going to be a delinquent.”

Parenting and other social factors can completely override the influence of the genes, he said.

From an evolutionary perspective, aggressive behavior might be beneficial. According to the UNC-CH team’s research, which will be published in the August edition of American Sociological Review, boys who tend to be more aggressive could have advantages when it comes to getting a mate, protecting their families and getting enough food.

Studies of violent behavior among wild chimpanzees suggested to the study’s authors that “human violence is rooted in pre-human history.”

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