A New York federal judge's order that the Obama administration must make emergency contraception available to women of all ages places new emphasis on the need for comprehensive sex education in America's schools.

Some critics fear making the so-called morning-after pill available without age restrictions - combined with today's easy access to condoms and other birth control - will lead to more teenagers becoming sexually active.

There's no evidence that such a prediction will come true. But the possibility, placed in the context of what is already known about teenage sexuality, shouldn't be dismissed out of hand.

Recent studies show 70 percent of American girls and 63 percent of boys have had sexual intercourse by age 18. As a result, U.S. teens experience 850,000 pregnancies annually, and the U.S. Centers for Disease Control and Prevention say one in five births to U.S. teenagers is not a first child.

Add to the pregnancy numbers statistics on sexually transmitted diseases among teens, and the need for effective sex education becomes even greater. In Philadelphia, for example, the highest rates of gonorrhea and chlamydia are among teenagers, ages 15 to 19.

In the court case, U.S. District Judge Edward Korman overturned the Obama administration's decision to make the emergency-contraception pill also known as Plan B available without a prescription only to those 17 and older. The drug is kept behind the counter at pharmacies, and purchasers must show a government-issued ID to prove their age. Korman's ruling, if allowed to stand, would put an end to those restrictions within 30 days.

The U.S. Justice Department has not yet announced whether it will appeal the ruling, but the White House says President Obama, the father of two adolescent daughters, still supports the decision of Health and Human Services Secretary Kathleen Sebelius two years ago to place age restrictions on the drug.

"I think it is important for us to make sure that we apply some common sense to various rules when it comes to over-the-counter medicine," Obama said in 2011. But given the criticism he is getting from his liberal base now for his proposed budget cuts to Medicare and Social Security, the president may not fight too hard against Korman's ruling.

Advocates for giving teenage girls easier access to emergency contraception make a valid point in saying they are more likely to need it. The pill can reduce the chances of pregnancy by up to 89 percent if taken within 72 hours of unprotected sex.

But condoms and morning-after pills are no replacement for what a teenager can learn in a comprehensive sex education class.

Research shows highly effective sex education and HIV prevention programs delay the initiation of sex while reducing the frequency of sex, the number of new partners, and the incidence of unprotected sex. Abstinence-only programs aren't as effective. In fact, studies show 88 percent of participants in virginity pledge programs have sex prior to marriage, and they are less likely to use contraceptives when they have sex.