Here’s what past research on bullying has told us. Parents of bullies are often distant or domineering. Parents of victims tend to be over-protective.

Presumably, such findings, have influenced many anti-bullying programs which include sessions for parents on how to prevent your child from becoming (or remaining) a bully or a victim. But findings from a recent study are calling the perceived wisdom of this approach into question, and, for the first time, researchers have been testing the possibility that parents can somehow cause their children to bully or to be bullied.

Harriet A. Ball and colleagues at the Social, Genetic, and Developmental Psychiatry Centre at Kings College, London noted that no past studies of the association between parenting and bullying took into account genetic influences. So, for example, bullies might bully due to their experiences with domineering parents, but it’s also possible that a bully inherits genes from his parent that make him aggressive.

They took the standard approach to assessing whether genes account for a particular behavior by looking at the behavior of both fraternal and identical twins. The basic idea is this: if something in the twins’ “shared environment” (meaning a situation that is common to both members of the pair, such as their parenting or family context) accounts for their behavior, then identical twins (who are genetic duplicates of one another) should be no more similar than fraternal twins (who share, on average, only 50 percent of their genes). However, if identical twins are more similar to one another than are fraternal twins, then a genetic influence is probable.

The Kings College study used data from surveys of mothers and teachers of 1,116 pairs of 10-year-old twins in England and Wales. The research team found that kids’ tendencies to bully or to be victimized was largely explained by their genetic make-up. Children’s “shared environments” – which include their parenting – did not account for their bully or victim status.

Thus general parenting approaches do not seem to influence kids’ bullying or victimization. Beyond genetics, children in the study appeared to be influenced by environmental factors they didn’t share with their twins. This could include interactions with peers that affect each twin differently.

So parents seem to be off the hook. But the researchers note that more research is needed to establish exactly which genetic tendencies influence behavior in bullying situations and what types of circumstances encourage or discourage the expression of such tendencies.

• Summary of “Genetic And Environmental Influences On Victims, Bullies And Bully-Victims In Childhood” by Harriet A. Ball, Louise Arseneault, Alan Taylor, Barbara Maughan, Avshalom Caspi, and Terrie E. Moffitt in Journal of Child Psychology & Psychiatry, Jan 2008, Vol. 49, Issue 1, pp104-112.

First published in Prevention Action on January 17th 2008.