So often studies tell us what we already know.

Last spring, the National Campaign to Prevent Teen Pregnancy, armed with the results of two decades of research, concluded that children who have strong, positive ties to their parents are less likely to be sexually active, and more likely to protect themselves if they become sexually active.But each year 1 million teenagers do become pregnant, and most teenagers say a major reason is that their parents don't talk with them about sex.

For more than 25 years, clinics supported by the Title X family planning program have provided young people with a safe place to receive information, counseling, and contraception. Many come with their parents' full knowledge and support; all are encouraged to tell their parents.

But there's a terribly wrong-headed effort being made in Congress to change that.

In July, the House Appropriations Committee voted to deny teens confidential family planning services at public health clinics participating in the Title X program unless they first notify their parents.

This is a puzzling policy. Congressional supporters of this restriction are very much against abortion. Yet access to contraception is the most effective means to prevent abortion.

It is also a dangerous policy. Young people will be denied the means to prevent unintended pregnancy and sexually transmitted infections that, left untreated, could lead to infertility, even death.

The safest course for young people is abstinence. Almost everyone agrees that teens should be taught to abstain from sex. But no one will benefit if we ignore the facts:

- Half of U.S. teens are sexually active;

- Sexually active teens who don't protect themselves have a 90 percent chance of becoming pregnant in one year;

- Half of teens who don't already inform their parents say they would stop seeking family planning services if they had to involve a parent.

For these reasons, the American Medical Association, the American Academy of Pediatrics, and the American Academy of Family Physicians all oppose mandatory parental consent or notification requirements for young people seeking family planning services. Most Americans understand the risks - two-thirds want teens to have confidential access to birth control, according to a Lake Research poll.

Planned Parenthood cares for thousands of teens each year. We know that they are far more able to make responsible choices when they receive education and counseling along with medical care. Moreover, we know that teenagers especially will not seek help where there is no trust. Parental notice requirements for Title X clinics would institutionalize that distrust.

Parents should assume the major role in helping their children make responsible choices about sex; with all of its social and public health implications, it's natural that we expect that they do so. But it makes no sense to punish teens who lack resources at home by denying them vital professional help elsewhere.

We don't need a study to tell us the obvious. We already know better - and so should Congress.