While tumors, brain disease, certain forms of epilepsy, and premenstrual syndrome have been directly associated with certain kinds of criminal behavior, most biological factors show only an indirect relationship. While there is some evidence for the influence of genetic factors, specific to sex and type of criminality, such factors act in concert with and are modified by various other factors such as social class, rearing, and type of environment. Attention deficit disorder appears to be associated with increased risk of adult antisocial behavior. Studies of inmates in general, and psychopathic inmates in particular, have identified a lowered responsivity of the electrodermal and cardiovascular system and of the adrenal glands to anticipation of a noxious event. These differences may have a genetic basis and may contribute to an inability to learn to passively avoid acts that lead to negative consequences. Overall, knowledge of the role of biological factors in criminality is limited. An improved understanding of the complex causal chains that determine criminal behavior is essential for the development of successful prevention programs. 5 annotated references. (Author summary modified)