This study evaluated the usefulness of the “Sexual Activity Scale”(SAS; Vargas & Barrera, 2002) to predict the early onset of penetrative sex. A total of 591 adolescents (260 women, 331 men) responded to the five items of the scale in five independent studies in Bogotá, Colombia. The factor analysis confirmed two factors: one of conventional expressions of affection and another that includes pre-penetrative and coital practices. The logistic regression analysis revealed that from the age and the score in the first four items of the EAS