The new statistics confirm that study's findings that oral sex is very much part of the teenage sexual repertoire. According to the survey, more than half of all teenagers aged 15 to 19 have engaged in oral sex - including nearly a quarter of those who have never had intercourse.

Men aged 30 to 44 have had a median of six to eight sexual partners in their lifetimes; the women's median was about four.

Among men and women aged 15 to 44, about two-thirds have had only one sexual partner in the past year. Ten percent of men and 7 percent of women have had three or more partners.

About 4 percent of men and women described themselves as homosexual or bisexual. But in a finding that surprised the researchers, 14 percent of women aged 18 to 29 reported at least one sexual experience with another woman, more than twice the proportion of young men who reported having had sex with another man.