Everybody knows that when teen-age girls get pregnant, the fathers of those babies are their teen-age boyfriends, right? Wrong, says a collection of new studies. More than 50 percent of the fathers of babies born to mothers between the ages of 15 and 17 are adults aged 20 or older. According to a California study of 47,000 births to teen-agers in 1993, two-thirds of the babies were fathered by men who were beyond their high school years.
The younger the teen-age mother, the greater the age difference. The California study found that among mothers ages 11 to 15, only 9 percent had had sexual relations with classmates. Forty percent had been impregnated by high school boys, and 51 percent of the fathers were adults.
These data ought to give pause to those who believe that handing out condoms in junior high and high schools will stem the tide of unwed parenting among teen-agers.
Condom enthusiasts always argue that while they personally are not in favor of premature sexual activity among teen-agers, we must be realistic. The kids are going to do it anyway, so we might as well make sure they have the capacity to protect themselves against the potentially tragic consequences -- including unwanted pregnancy and disease -- that could ensue. After all, everyone remembers what it feels like to be a teen-ager -- and you cannot repeal puberty.
Now, in the first place, liberals who protest that they don't want kids engaging in sex are not being truly honest. If you don't want kids to do something, you forbid it; you don't simply protect them from the consequences of their actions. There is near unanimity in this country about kids and drugs. We are certain that we want kids to stay away. And our policies reflect that certainty. We don't give kids the message, ''Listen, you're not old enough to take drugs responsibly. But if you do decide to partake anyway, here are clean needles and syringes to prevent the worst consequences of your actions.''
The condom distributors don't really care if kids are chaste. They just want them to be healthy.
But the image that many liberal adults have of the world of teen-agers is quite naive and out of touch. It is not, as data from the Alan Guttmacher Institute and other researchers show, a rock 'n' roll carnival of randy fun. It has gotten rough out there.
According to the New York Times, a Chicago study found that 61 percent of teen-age mothers said they had been abused, often by the fathers of their babies, some starting as early as age 11.
This does not come as a surprise to Elayne Bennett, founder of Best Friends, an abstinence program for young girls. Her students have been telling her for years that men look for younger and younger girls as sexual partners. Virgins are prized not so much for their virginity per se, but because the man feels sure he needn't wear a condom to protect himself for AIDS or other sexually transmitted diseases. She has also noted the large numbers of young girls who admit that their first sexual encounters were involuntary.
In other words, the world of teen sex is not the playground some adults may imagine. It is a world characterized by statutory and actual rape. It is a world in which sex has replaced love. Popular music aimed at teen-agers, once romantic and longing, has become coarse and vulgar. Whereas teen-age boys once ''pinned'' their sweethearts to show their devotion, many
teen-age boys today are unwilling to acknowledge their girlfriends in public, even as they have total access to their bodies in private.
Frederica Mathewes-Green, writing in Policy Review, notes that teen-agers are quite sour on the sexual revolution. A 1994 Roper survey found that 62 percent of sexually experienced high school girls and 54 percent of all high schoolers said they wished they had waited. When an Emory University study of 1,000 ''sexually active'' teen-agers asked what subject the girls needed more information on, 85 percent checked ''How to say no without hurting the other person's feelings.''
Even if premarital sex does not offend one's religious sensibilities, the news from the front is cause for deep moral concern.
Mona Charen is a syndicated columnist.