School-based sex education is a contentious issue in contemporary American society. At its most basic level, the debate centers on the division between abstinence-only and comprehensive sex education. Abstinence-only advocates promote a sex education curriculum that presents refraining from all sexual activity outside of marriage as the only effective way to prevent unwanted pregnancy and sexually transmitted diseases. Comprehensive advocates promote a sex education curriculum that presents multiple strategies beyond sexual abstinence - such as proper contraceptive use - for preventing unwanted pregnancy and sexually transmitted diseases. Both sides harbor strong values and moral convictions that lead them to believe that their way is the best way and that their way should prevail when it comes to social policy. This thesis examines the literature on both types of programs in an attempt to determine what the evidence-based approach to effective sex education programming should follow.