See , 
Among Hass's American teenagers, 8% of the 13-year-old boys had had their penises sucked by a girl, and 11% licked a girl's vulva. With the 15-year-olds these percentages had increased to 35% and 53%.
Hass proposed to his subjects the following: "i think it is important for a boy to have sexual experience with a few different people before he settles down with one person." Of the 15-16-year-old girls, 59% agreed (boys 65%), of the 17-18-year-old girls, 64% agreed (boys 59%). Only 15% and,resp. 17% of the girls thought a boy should be a virgin when he got married. The figures for boys were 8% and 9%.
"Do you feel you can be open with your parents about sex?" 66% of the boys replied No. (p. 166)
"What kinds of things about your own sex life do you tell your parents?"
I tell them only what they would approve of. - 20%
I tell them almost everything. - 9%
I tell them nothing about my sex life. - 26%
I only talk in a general way about sex, not specifically about me. - 45%
cited by Brongersma 1990 p.222, 282