There have been several pieces of legislation passed to deal with sex offenders in the US since 1994. This includes laws requiring sex offender registration, community notification, and the establishment of a national sex offender database. Research shows that rape is often underreported, with acquaintance rape making up a large percentage of cases. Characteristics of both rapists and victims are discussed, as well as typologies of rapists and causes of rape behavior. Treatment of sex offenders focuses on cognitive behavioral therapy and relapse prevention with high recidivism rates.