Genetics and violence

Scientific interest in the correlation between genetic factors and violence dates back to the eugenics movement of the 19th century. Because of the Nazi and racist associations with eugenics, this study fell into disrepute from the 1960s through the 1980s, when the prevalent view was that environment was the primary determinant of behavior. With the advance of genetics in the beginning of the 21st century there has been renewed interest in finding possible genetic causes for crime and violence.

Studies
A rare genetic variant causing MAO-A deficiency has been associated with violent behavior in males. In 2002 a study published by researchers at King's College London found a link between a genetic variant causing low levels of MAO-A and increased levels of antisocial behavior in people who had been mistreated as children.

An American group studying monkeys called MAO-A a "warrior gene" in 2004.