The most controversial theory of crime and deviance is that differences among individuals may have some genetic basis. By a “genetic basis of deviance,’ I mean that the probability that a given individual who persistently breaks the ordinary criminal law will be influenced to a significant degree by dispositions that have been inherited. I wish to defend that theory, all the while acknowledging that it is not the whole story, not simply to convince you to believe it, but to persuade you to that there is nothing perverse, reactionary, or fatalistic about accepting the fact that most important forms of human behavior, including deviant forms, are influenced by our biological makeup and our evolutionary past. It is important that you be persuaded of this because it is impossible to carry on an intelligent discussion of crime prevention if for political or ideological reasons we rule out of consideration an entire set of possible causes.