Abstract The family is one of the most important socializing agents in adolescent sex education. However, multiple barriers to communication within families have been identified. Therefore, this study aimed to characterize and understand the processes by which parents and their adolescent children communicate about sexuality. Two questionnaires were completed by 711 fathers/mothers and 566 male/female students in 21 schools in Cali (Colombia), and 15 discussion groups were formed. The results showed that conversations about sexuality focused on protection for women and on sexuality promotion for men. Furthermore, it was found that greater fluency exists in father/son and mother/daughter conversations. The largest discrepancy between parents and teenagers was the adults' belief that it is sufficient to mention certain topics in a directive manner and the children's expectations that parents will discuss the value and dynamics of the sexual experience. Embarrassment and lack of communication tools hinder communication processes.