A substantial minority of sexual offences against children are carried out by children. This article examines a case of pre-pubescent sexual offending associated with repeated reconstructive surgery to the penis, in the treatment of the congenital deformity hypospadias. Although the surgery involved was appropriate, the patient appeared to experience it as a form of recurrent sexual abuse. Subsequently the patient escalated from exhibitionism to contact sexual offences which cognitive-behavioural treatment failed to modify. We discuss the case with reference to concepts of trauma-organized systems, with a particular focus on the timing and context of surgery. We suggest that this case demonstrates that repeated genital surgery in a child may be experienced as childhood sexual abuse even with sensitive management. It emphasizes the roles of aggression and social validation in sexual offending, and it supports the proposed inclusion of ‘Sexual Arousal Disorder of Childhood’ in DSM-IV and ICD-10.