Sex offender registries in the United States exist at both the federal and state levels. These registries contain information about persons convicted of sexual. Offenders are classified based on their risk of re-offending and the degree of danger they pose to the public. A sex offender is any person who lives, works, or attends school in Massachusetts who has: Been convicted of a sex offense. Been adjudicated as a youthful offender or as a delinquent juvenile for a sex offense.