Abstract
Adolescence is a period of transition between childhood and adulthood. The article aims to study the individual, family and school characteristics of adolescents beginning their sexual lives. The database we used was the 2015 PeNSE (National Adolescent School-based Health Survey) and the methodology was the survival analysis. The results show that boys initiate sexual activity before girls and risky behaviors associated with the use of licit and illicit drugs increase the chance of having early sex. In addition, this work highlights the importance of parental practices in reducing the chances of beginning sexual activity, as well as the presence of school workshops on the risks of pregnancy. It should be noted that intervention strategies need to be differentiated according to gender in order to increase effectiveness.