Why so many teenage virgins?

When John Belushi starred in Animal House in 1978, critics variously called the movie raunchy, offensive, and hysterically funny. Today it seems merely quaint. The popular culture of American teenagers has shifted significantly over the past three decades. John Belushi burping and crushing a beer can against his forehead wouldn't shock anybody today, in the era of Superbad, Jackass 3, and Zack and Miri Make a Porno.

So the CDC findings—that teenagers today are getting less action than teenagers did two decades ago—may come as a surprise to many. Let's take a closer look at the CDC study released last month. CDC investigators interviewed a demographically representative sample of 4,662 teens from across the country, asking each teen—in a structured one-on-one interview—whether she or he had ever had intercourse. Then the researchers compared those results with results from previous studies. In 1988, 51 percent of never-married young women 15 to 19 years of age reported that they had had intercourse at least once; that's now down to 43 percent. The decline for young men has been even steeper. In 1988, 60 percent of never-married young men 15 to 19 years old reported that they had had sexual intercourse; today that figure is just 42 percent.

Quite a drop. What happened? And why is the reduction among boys—a reduction of 18 percent, from 60 percent to 42 percent—more than double the girls' decrease of 8 percent, from 51 percent to 43 percent?

I have visited more than 200 schools across the United States. I have talked with kids in cities, in suburbs, and in rural areas. I think I know why fewer teens are having sexual intercourse compared with 20+ years ago. It's pretty simple. Oral sex is displacing old-fashioned penile-vaginal intercourse. The CDC report concerned only penile-vaginal intercourse. The CDC interviewers did not mention oral sex, except to make sure that each teen understood that the interviewer was asking about vaginal intercourse, not oral sex.

Among sexually active teenagers in the 1980s, vaginal intercourse was far more common than oral sex. Today oral sex is much more widespread than it was 20 or 30 years ago. I see two reasons why.

Reason #1: The dating culture which prevailed in the 1980's and earlier has been replaced by culture of the hookup. In a dating relationship, intimacy occurs in the context of a romantic relationship. In a hook-up, it's understood by both parties that no relationship is involved—and often none is wanted. Who hooks up with whom at the party is determined primarily by rank order in popularity. The most popular girl at the party hooks up with the most popular boy. Providing oral sex to the boy is just part of the job description, if you're a popular girl. "I'd rather do that, than kiss him," one girl told me, referring to oral sex. "If I kiss him I have to pretend that I like him." In the great majority of cases, the oral sex is provided by the girl for the boy, not the other way around. The hookup culture—with its freedom from commitment and obligation—accommodates oral sex more readily than vaginal intercourse.

Reason #2 is the explosion in the availability of pornography. In 1990, many 16-year-olds had never seen a photo of a couple having oral sex. Today, any 13-year-old can type the word "oral" in any browser and, willy-nilly, links to free videos of oral sex will pop up. Children and teens look to adults for guidance about what grown-ups do. Today, many kids are looking to the Internet. Oral sex is ubiquitous in pornography, and pornography is everywhere on the Web.

In my conversations with teens and young adults, I'm seeing a down side to this emerging culture, a culture in which oral sex—with the girl on her knees servicing the boy—is becoming the primary form of sexual intimacy. It depersonalizes intimacy. It sends the message that sexual satisfaction is a commodity which females provide to males. Once the boy ejaculates, that's usually the end of it. Rarely does a teen describe a hook-up in which the boy, after ejaculating, asks the girl "Now what can I do for you?"

And it may lead to less satisfying intercourse, when that young person finally does "go all the way." The boy who has grown accustomed to a girl on her knees providing him with sexual satisfaction may not understand that intercourse should be an interaction between the woman and the man. "He's still masturbating; he's just using my body instead of his hand," is what one frustrated young woman told me. "He doesn't have the foggiest clue what would please me, and he has no interest in finding out."

So what should we do, as parents? At many schools, I find that sex education is mostly about risky sex versus safe sex or abstinence. Some high school students have even told me about sex-education classes where the instructor has praised pornography as a form of safe sex. You can't get a sexually-transmitted disease by masturbating over porn.

We can't rely on the schools to teach kids what we want them to know: namely, that sexual intimacy should be first and foremost about intimacy—knowing and caring about your partner. We need to teach this to our children, ourselves.

Why is pornography harmful for teenagers? Because it turns a person into an object. Because it presents an unrealistic portrayal of sex. Because it invites comparison of the real girl in the bedroom with the porn star wearing lingerie. I emphasize that I am NOT against pornography for adults. If you and your partner like to look at pornography, great. If you and your partner like to drink Tequila, that's great too. Just because Tequila is OK for adults doesn't mean it's OK for 14-year-olds. Just because pornography is great for some grown-ups doesn't mean it's OK for 14-year-olds.

Speaking as the father of a daughter, I say: We need to teach teenage girls to get off their knees.

Maybe we should encourage girls and boys to go on more dates, rather than hooking up. Maybe they could go to an art-house theater showing one of the old classics, like Animal House.

Leonard Sax MD PhD is a physician, psychologist, and author of Boys Adrift (Basic Books 2007) and Girls on the Edge (Basic Books 2010). He can be contacted via his web site, www.leonardsax.com.