May 20, 2024

Gene of the Week 1: sex offending

“Sex offending is written in DNA of some men” in the headlines after publication of a Swedish study.

The father of modern criminology, the Italian sociologist Cesare Lombroso (1835-1909) believed that criminality was genetically determined. A “born criminal” could be detected by the presence of a long list of “stigmata” such as an asymmetrical faces, sloping forehead, large ears or left-handedness. This idea has been largely discredited, but, it flowers as soon as water floods the desert sands.

Newspapers last week featured headlines like: “Sex crimes may run in a family’s male genes” or “Genetic factors were found to increase the risk of a sex crime conviction” or “Sex offending is written in DNA of some men” after the release of a Swedish study of the genetic link to sex crimes.

Researchers at the Karolinska Institutet in collaboration with Oxford reported in the International Journal of Epidemiology that close relatives of men convicted of sexual offences commit similar offences themselves more frequently than comparison subjects. This was due to genetic factors rather than shared family environment. They found that about 2.5% of brothers or sons of convicted sex crime offenders are themselves convicted for sex crimes. The equivalent figure for men in the general population is about 0.5%. 

As the Daily Mail helpfully pointed out, the late Jimmy Savile, the notorious British entertainer who allegedly abused hundreds of people, many of them children, had a brother (now deceased) who is also suspected of having committed several sex offenses.

“Importantly, this does not imply that sons or brothers of sex offenders inevitably become offenders too”, says Professor Niklas Langstrom, the study’s lead author. “But although sex crime convictions are relatively few overall, our study shows that the family risk increase is substantial. Preventive treatment for families at risk could possibly reduce the number of future victims.”

What does he mean by “preventative treatment”? First of all, the fathers and brothers of sex offenders could be offered psychological counselling to foster awareness of sexual boundaries and help in conflict management. Second, “psychological and pharmacological help to decrease individual risk factors such as cognitive distortions, emotional instability and hypersexuality”.

A journalist with the journal Science, Emily Underwood, suggested that the results should be taken “with a generous dash of salt” because of limitations with the data. “We’re a long way from pinning down genes that can explain why a person commits rape or any other sex crime.”

Nathaniel Comfort, an historian of genetics at Johns Hopkins University was less restrained. “Can you believe this? A family correlation taken as a genetic link–for a predisposition to crime. This is so simplistic it’s like 1910 all over again. It’s not back to the future–it’s ahead to the past.”
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