Of one hundred fathers of autistic children, eighty-five were found to be obsessive, detached, and humorless individuals, perfectionistic to extreme and with remarkable lack of empathy for, and sensitivity to, the feelings of others. Fifteen of the fathers were described as warm, generous, and devoted and in four of the families neither parent exhibited obvious psychopathology. These fathers of autistic children reared an equal number of normal offspring. There was a total absence of overt psychosis among the fathers although one was alcoholic and another had exhibited an acute anxiety neurosis. Eisenberg believes that these facts imply the existence of what most people call a constitutional factor in early infantile autism.