of sexual activity, tobacco use and alcohol use, and “adolescent dual problem” profile (for girls, characterized by the mid-adolescent initiation of sexual activity and tobacco use also conferred risk for teen pregnancy (0.35 for boys; 0.72 for girls) and STDs for girls (0.26). In contrast, youth in the third risk profile initiated tobacco and substance use in preadolescence, but delayed sexual activity thereby rarely experiencing teen pregnancy or STD.
