Substantial proportions of both males and females in the United States and Canada have experienced sexual assault. Various studies have shown positive correlations between plasma testosterone levels and sexual aggression as measured by questionnaires on aggression. Clinical experience has also shown that sexual offenders tend to conceal the true nature of their deviant sexual arousal patterns and behavior. However, the psychophysiological assessment method developed by Freund can identify most sexual offenders as well as their responses to treatment. Sexual questionnaires also aid the assessment of sex offenders. Treatment aims to help offenders reduce their deviant sexual arousal, based on either an antiandrogen treatment program or a behavioral treatment program. 76 references