Prevalence of first sexual intercourse before age 14 and forced sexual intercourse in the 2004 Pelotas Birth Cohort

The study described early sexual initiation, forced sexual initiation, and associated factors in young participants of a Brazilian birth cohort.

Participants who, at the 18-year-of-age follow-up, answered yes to the question "Have you ever had sexual intercourse (had sex)?" were included. They were asked about age at first intercourse (< 14 or ≥ 14) and whether it was consensual ("because I wanted to" or "because I was forced"). Factors associated with these outcomes were analyzed by Poisson regression with robust variance according to a hierarchical model.

The sample consisted of 3255 participants, with a prevalence of sexual intercourse before 14 years of age of 13.3% and of forced first sexual intercourse of 1.6%. First intercourse before 14 years of age was more likely to occur in boys, those who identified as asexual or in the category "other" when asked about their sexual orientation, who currently used drugs daily/almost daily, whose first sexual intercourse was forced, and who had more lifetime sexual partners. First forced sexual intercourse was more likely to occur in girls, those who identified as pansexual, who had sexual intercourse before 14 years of age, and who had more lifetime sexual partners.

Better guidance is recommended for adolescents regarding sexual abuse and violence and methods of self-preservation and reporting.