The application of psychological theory and research to understanding human sexuality is not a new phenomenon. However, the application of genital devices to the measurement of specific aspects of sexual arousal is emerging as an important area of research in the forensic domain given the recognition of the increased numbers of women who are abusing children. Although controversial, phallometric measures of sexual arousal have had considerable success with male offenders both in the assessment and treatment of deviant arousal and disorders of sexual preference. Deviant arousal patterns are now known to be predictive in re-offending and treatability but the reliance on selfreport measures creates difficulties for clinicians as they are likely to be biased by response tendencies. Therefore, the challenge now facing forensic and clinical psychologists is how to assess genital arousal in women with a view to assessing deviant sexual interest. The main aim of this paper is to explore the physiology of female sexual arousal and to consider the implications of using psychophysiological measurements with women in a forensic context. © 2008 by The Psychological Society of Ireland.