Boys who carry a variation of the gene Monoamine oxidase A, are more likely to join gangs and be among the most violent members, U.S. researchers said.
Criminologist Kevin M. Beaver at Florida State University said the findings apply only to males -- not girls with the same variant of the so-called "warrior gene."
"While gangs typically have been regarded as a sociological phenomenon, our investigation shows that variants of a specific MAOA gene, known as a 'low-activity 3-repeat allele,' play a significant role," Beaver said in a statement. "Previous research has linked low-activity MAOA variants to a wide range of antisocial, even violent, behavior, but our study confirms that these variants can predict gang membership."