Health promotion should be evidence-based, needs driven, subject to evaluation, and ecological in perspective. How can this be achieved in the context of school-based sex education? Adopting new behaviors and giving up old habits involves common decision-making, planning, motivational control, and goal prioritization processes. Consequently, despite the particular nature of sexual behavior, models of cognitive change applied to other health-related behaviors also apply to the promotion of safer sex practice. Young people are less likely to have unprotected sexual intercourse if they have acquired a variety of social skills relevant to dealing with romantic and sexual relationships. Many of these social skills and the methods employed to facilitate their development are also important to the promotion of other health behaviors. However, teaching social skills relevant to sexual behavior in classroom settings requires specialist expertise both in program design and in delivery by teachers or facilitators. Theory- and evidence-based programs designed to promote such skills and modified on the basis of effectiveness evaluations are most likely to have an impact on the rate of pregnancies and sexually transmitted infections among young people. Yet, such programs may not be used in schools because of policy and cultural constraints. When this is the case, optimally effective health promotion cannot be delivered. Health promoters should acknowledge these challenges and facilitate the adoption and implementation of effective sexual health promotion programs by targeting communities and legislators.