This paper was presented at the Conference on Forensic Psychology and Psychiatry, held in September 1979, by the New York Academy of Sciences and cosponsored by the Department of Justice, National Institute of Law Enforcement and Criminal justice. The primary prevention of the onset of criminal behavior involves (1) ecological alterations (environmental manipulations), (2) societal changes that would stimulate the recognition that some forms of criminal behavior have individual psychological or biological predispositions, (3) research development. The Wadsworth Study in Great Britain examined the relationship of subsequent delinquency to a childhood measure of autonomic nervous system responses to anticipation of stress and found that those who were eventually registered as delinquents at 21 years of age had had a lower pulse rate increase in anticipation of the stress at age 11. In a Danish study the 7 boys (of 104) who were subsequently reported delinquent exhibited a predelinquency skin conductance level, responsiveness, and recovery below that of the controls. In addition, Hare's Study in 1964 showed that skin conductance recovery predicted degree of recidivism 10 years later. All three of the studies are consistent with a description of the predelinquent and prerecidivistic criminal having somewhat underreactive autonomic nervous systems. Very little of predictability of antisocial behavior can be concluded from family studies data because it is difficult to disentangle heredity and environmental influences. However, the results of twin studies do not contradict the hypothesis that some genetically transmitted, biological characteristics predispose to antisocial behavior. This research suggests that for a child to effectively learn to be civilized, there must exist a social censuring agent (family or peers), an adequate fear physiological response, the ability to learn the fear response in anticipation of an antisocial act, as well as the fast dissipation of physiological fear to quickly reinforce the inhibitory response. Thirty references are appended.