A 20 year old female pedophile exhibiting multiple paraphilias and who had been both a victim of incest and an active participant, undertook extensive clinical, psychometric, endocrine and laboratory sexual arousal studies. Her psychiatric, psychometric and physiologic arousal profiles showed similarities to those of a sizable proportion of male child molesters, especially incestors. It is suggested that laboratory arousal tests (using the vaginal photoplethysmograph) may have a role in the assessment of some female sex offenders.