It isn't just the choices. Young people are having less sex. Japan has noticed this. Declining sales of contraceptives but declines in both STDs and pregnancies, especially amongst the young. Incidents of the "oops we are pregnant" scenario have declined all over the western world. Western culture has for decades complained that young people have too liberal a view of sex. Remember those abstinence pushes in the 80s and 90s? Remember purity rings? They worked.