The source of information matters: Teens who say they've gotten most of their information about sex from friends rather than from teachers or parents, are two to three times likelier to engage in sexual touching, oral sex and sexual intercourse.
A comfort level is important. Among teens who've discussed sex with their parents, more than eight in 10 say they're comfortable doing so, and nearly nine in 10 say the discussion answered most of their questions. But among those who haven't spoken with their parents about sex, only about half say they'd be comfortable doing so.
As noted, the value to parents of developing that comfort and dialogue is clear: Among sexually active teens, 76 percent of those who talk with their parents about sex say their parents know at least something (if not everything) about their sexual activity. But among those who don't talk, just 43 percent say their parents know anything at all about what they're up to.
Communication from parents might counter other, competing messages and hazards. As noted, more than half of teens say they get at least occasional e-mail spam or pop-up ads about sex or pornographic Web sites; nearly a quarter get them "very often."
Nearly three in 10 have visited porn Web sites, rising to 51 percent of boys ages 15 to 17. A third have visited an Internet chat room where sex was being discussed -- rising to half of 17-year-olds (boys and girls alike). Among teens who've visited such sites, 9 percent, nearly one in 10, say they've participated in online sex chats.
There's clearly a significant level of sexual activity among teens. Seventy percent say "most" or "a lot" of the teenagers they know engage in romantic kissing; 46 percent in intimate touching; 24 percent in oral sex; and 27 percent in sexual intercourse. And these numbers are higher among older teens, age 15 to 17.
In terms of their own activity, 63 percent of 13- to 17-year-olds say they've kissed romantically, rising to 73 percent of those 15 and up. Forty-four percent report sexual touching; among older teens, it's 55 percent. Nineteen percent of all teens, and 27 percent of older teens, say they've had oral sex. As many have had sexual intercourse.
These are not all ongoing activities: Fifteen percent of all teens, and 20 percent of older teens, say they're "currently involved" in a sexual relationship.
All these sexual activities rise with age -- they're lowest by far at age 13, rising sharply at age 14, and then jumping again particularly at age 17.
Among 13-year-olds, for example, 36 percent have kissed romantically; at 14 it shoots up to 61 percent, and among 17-year-olds it's 84 percent. Fifteen percent of 13-year-olds report sexual touching; that more than doubles to 38 percent of 14-year-olds, then jumps to 63 percent of 17-year-olds.
The biggest jumps in oral sex and intercourse occur later, from ages 16 to 17. About a quarter of 16-year-olds say they've had oral sex, and 21 percent say they've had sexual intercourse -- sizable numbers in themselves but ones that spike to 42 and 43 percent among 17-year-olds.
While teens who've had intercourse report an average of four partners, that's boosted by a few who report particularly high numbers of partners (as many as 53). The median -- half are higher, half lower -- is two partners.