The sexually abused-sexual abuser hypothesis posits that persons, especially males, who are sexually abused as children are at particular risk of sexually abusing others later in life. We tested this hypothesis by prospectively examining associations between maltreatment and offending in a birth cohort of 38,282 males with a maltreatment history and/or at least one finalized offense. We examined these associations within the context of the wider birth population. Proportionally few boys were the subject of official notifications for sexual abuse (14.8% of maltreated boys, and 1.4% of the birth population); proportionally very few of these sexually abused boys (3%) went on to become sexual offenders; and, contrary to findings typically reported in retrospective clinical studies, proportionally few sexual offenders (4%) had a confirmed history of sexual abuse. Poly-victimization (exposure to multiple types of maltreatment) was significantly associated with sexual offending, violent offending, and general (nonsexual, nonviolent) offending. We found no specific association between sexual abuse and sexual offending, and nor did we find any association between sexual abuse and sexual offending specifically within the poly-victimized group. The total number of sexual abuse notifications did make a small unique contribution to the variance in sexual offending compared to other offending. Implications concerning maltreated boys and male sexual offenders are discussed.