Relatives of Rapists More Likely to Offend, Finds Study

Researchers found that brothers and fathers of sexual offenders were five times more likely to offend themselves, picture taken December 17, 2007. Dario Pignatelli/Reuters

Male relatives of sexual offenders are up to five times more likely to commit similar offences, researchers have found.

The Swedish-led study also revealed that genetic factors explain around 40% of the liability to commit sexual crimes, rising to 46% in the case of child sexual offences specifically.

Among brothers and fathers of sexual offenders, 2.5% went on to offend themselves, compared to 0.5% of unrelated males.

Co-author Seena Fazel, professor of forensic psychiatry at the University of Oxford, believes that the findings should lead to preventative intervention with families of sexual offenders.

"These type of offences do run in families," says Fazel. "This doesn't mean in any way that it's inevitable these brothers are going to offend but there is an increased risk."

Fazel suggests that if social services are already working with high-risk families, those services may wish to "optimise" by offering advice on relationship management and impulse control to relatives. However, to publicly identify offenders' families due to the increased risk would be a "damaging and ostracising" move.

The study, published in the International Journal of Epidemiology, assessed more than 21,000 male Swedish sexual offenders over a 37-year period.

Shared environmental factors between siblings - such as parental example, upbringing and education - contributed as little as 2% to the risk of offending. Though the base rate for offending remained low among relatives of sex offenders, Fazel believes that the substantially greater risk for relatives is something which must be considered in forming government policy.

"It's only a piece in a big jigsaw, but it's still a piece and it should be part of the discourse in policy circles with something where we don't know a lot about what prevents sexual offending," he says.

Fazel believes that the research could be relevant to other high-income countries with similar rates of sexual offending to Sweden, such as the UK. The British ministry of justice declined to comment on whether the research would be taken into consideration.

The researchers did not identify a specific gene which leads to a greater propensity to commit offences but also suggested that psychological assistance and medication could be offered to relatives of sex offenders, if necessary, to help tackle emotional instability and hypersexuality.

The number of rapes and other sexual offences recorded in the UK are at the highest levels in the past 10 years. According to UK children's charity the National Society for the Prevention of Cruelty to Children, over 90% of child victims of sexual abuse were abused by someone they knew, such as a relative or friend.