Using information from the second Philadelphia birth cohort, it aimed to investigate the evolution of sexual offenders and sexual offences. Additionally, the relationship between juvenile and adult sex offences was explored, as well as the influence of juvenile sex offences on adult offences. The overall pattern seen was that juveniles who had sexually motivated police interactions had a high amount of non-sex contacts, a low prevalence of sexual recidivism, and a lesser propensity to continue their sexually inappropriate behavior into adulthood.