The manuscript addresses the problem of negative results of different indicators on sexuality and sexually transmitted diseases in Chile. The LGBTIQ community, females, children and adolescents are vulnerable groups in terms of bio-psychosocial and sexual well-being; they are therefore particularly affected and represented by this problem and its effects. The most important root causes are cultural and gender barriers and those preventing access to information. For this reason, having a comprehensive sex education (CSE) policy based on international standards is proposed as a means of solving the problem from the roots. The article analyzes the factors that influence the implementation of CSE as a public issue, reviewing the literature and comparing the cases of Costa Rica and Chile. We infer that the role of the feminist and LGBTIQ social movements constitutes an important factor.