This article provides a rigorous analysis of the legitimacy of continuing to rely on and promote school-based family life education, as a way of addressing concerns associated with sexual activity by adolescents. The issue is crucial because empirical evidence strongly suggests that a school-based approach, regardless of curricular content, has failed. For reasons grounded in law and policy, this article advocates that states should retreat from school-based family life education and, instead, recover the insights of the philosophical principle of subsidiarity. Recovering subsidiarity means fully respecting and giving effect to the parental right and duty to educate children in matters relating to morality, family life, and sexuality. Leaving this crucial task primarily to the family ensures not only efficient allocation of responsibility within society, but also a superior environment for effective and comprehensive family life education. This article also explores the key impetus behind the movement to get family life or sex education into schools, a movement grounded in a variety of ideologies. Because these ideologies are far removed from any genuine concern for the health and well-being of adolescents, the state interests often asserted as reasons for a school-based approach are insufficient to warrant continued infringement of the parental right and duty relating to the education and formation of children. Recovering subsidiarity will foster a parent-centered approach that is more likely to genuinely safeguard the well-being and reproductive health of the vast majority of adolescents.