Admissibility and Relevance of Behavioral Genetic Evidence in a Criminal Trial.

The New Mexico Supreme Court recently considered whether a trial court had erred in excluding behavioral genetic evidence of a murder defendant's low-activity monoamine oxidase A (MAOA) gene, which the defendant argued had predisposed him-along with his history of childhood maltreatment-to "maladaptive or violent behavior." After an extensive analysis of the underlying science and its relevance to the case, the supreme court held unanimously that the trial judge had the discretion to exclude the MAOA evidence. The court's analysis provides insights into how other courts are likely to rule on the relevance of behavioral genetic evidence.