"The first part of this article summarizes results from more than 200 studies that have found gender symmetry in perpetration and in risk factors and motives for physical violence in martial and dating relationships. It also summarizes research that has found that most partner violence is mutual and that self-defense explains only a small percentage of partner violence by either men or women. The second part of the article documents seven methods that have been used to deny, conceal, and distort the evidence on gender symmetry. The third part of the article suggests explanations for the denial of an overwhelming body of evidence by reputable scholars. The concluding section argues that ignoring the overwhelming evidence of gender symmetry has crippled prevention and treatment programs. It suggests ways in which prevention and treatment efforts might be improved by changing ideologically based programs to programs based on the evidence from the past 30 years of research."