Parents' contribution to sex education is increasingly receiving research attention. This growing interest stems from recognition of the influence that parental attitudes may have both on young people's sexual attitudes and behaviour, and on school-based sex education. Studies regarding parental attitudes towards sexuality are, however, still rare. The two main objectives of this study were to explore parental views about sexuality and to understand parental attitudes towards sex education. Four focus group discussions were conducted with parents from high schools in Cuenca, Ecuador. Data were analysed using thematic analysis. The study revealed that parents held a restricted view about sex education, grounded in traditional religious ideas about sexuality, which led parents to understand it as a morally and physically dangerous activity. Although parents expressed a willingness to make good quality sex education available to their children, they reported having insufficient personal resources to fulfil that objective. The results of this study provide important information about the need to develop and adapt sex education to each specific cultural context, thereby confirming the importance of knowing about the cultural traditions and religious beliefs that may form obstacles to effective sex education for young people in Ecuador.