In 1993, scientist Hans Brunner discovered that several male members of a large Dutch family who exhibited behaviors such as impulsive aggression, arson, and attempted rape possessed a mutant copy of the MAOA gene, the gene that codes for the production of the enzyme monoamine oxidase A (“MAOA”). Brunner and his colleagues demonstrated that carrier males produced less MAOA, or were “MAOA-low.” They hypothesized that this MAOA deficiency caused abnormal aggressive behavior in MAOA-low males. Subsequent research, however, demonstrated that the genetic mutation, acting alone, does not produce the abnormal, aggressive behavior observed by Brunner and his colleagues. In 2002, Avshalom Caspi and a team of New Zealand-based researchers published a ground-breaking study that demonstrated that MAOA-low males who experienced childhood maltreatment were likely to develop abnormal aggressive behavior and become violent offenders. This Note argues that Brunner and Caspi’s research can and should be used to prevent violent crime and to preserve the sense of peace and safety that is the foundation of free, civilized societies. More specifically, the Note proposes that states add a screening test for the MAOA-low genotype to their newborn screening programs and that states then offer “Part C” early intervention services to families with children who test positive for the genotype. The screening test would allow states to target a population of children at risk of criminal behavior. The intervention services—family education and counseling, home visits, parent support groups, and psychological and social work services— would prevent those at-risk children from suffering the maltreatment that would cause them to later develop aggressive, antisocial behavior. This Note examines the constitutionality and policy implications of the proposed legislation, presents a rudimentary cost-benefit analysis of the legislation, and ultimately concludes that it would pass constitutional muster and be a cost-effective public policy.