A 'violence' gene causes some children to be attracted to high intensity video games and films, researchers have claimed.
Dutch academics linked a gene variation to young people who sought and and engaged with violent media.
1,612 parents of children aged five to nine noted how much violent TV their children viewed, as well as how long they spent playing violent video games, as part of the study.
DNA samples collected at the children's birth were then analysed to identify the gene variant.
The researchers found that children carrying a specific variant of the serotonin-transporter gene on average consumed more violent media.
Those with the gene were also more likely to display ADHD-related behaviors.
Sanne Nikkelen of the University of Amsterdam's School of Communication Research said: "Our results indicate that children's violent media use is partly influenced by genetic factors.
"This could mean that children with this gene variant are more likely to seek out stimulating activities, such as violent television viewing and video game playing.
She added: "It is important to study the relationship between media use and ADHD-related behaviors because children who show increased ADHD-related behaviors often face peer and academic difficulties and are at increased risk for substance abuse.
"Examining factors that may contribute to the development of these behaviors is essential."