In 2006, the monoamine oxidase-A gene was widely reported in the media as being associated with risk-taking and aggressive behaviour in Māori. We examine the scientific evidence underlying this claim. Whilst there is credible evidence for a contribution of a monoamine oxidase-A genetic variant to antisocial behaviour in Caucasians, there is no direct evidence to support such an association in Māori. Insufficient rigour in interpreting and applying the relevant literature, and in generating new data, has (in conjunction with a lack of scientific investigative journalism) done science and Māori a disservice.