Adolescent sexual behaviour Nearly 70% of all unmarried females are nonvirgins by age 19 (80% of males). 25% of females have had sex by age 15 ; almost all these encounters were forced or coerced . Average age of first sexual experience is 16 years. Adolescents in the aggregate still drift into sexual activity rather than decide to have sex. Most adolescent sexual activity will take place in the context of one primary relationship. Most adolescents are not promiscuous, but "serially monogamous." Recent survey tells us that 57% of adolescents claim to have used a male barrier method during their last act. Research suggests that this might be an over statement . Most do not do what they say. More than 50% of sexually active adolescents do not use birth control regularly. This is what KAPLAN tells me! The point is that we should not let these problems creep into our society. We happen to be following every vice of the western world without hesitation thinking, or pretendi...