Parents: When you bought your children's new school supplies, did you make sure you had everything?

I mean, judging from the sex-education programs in place in many schools, you need more than just pencils, folders and notebooks. A trip to the "family planning" aisle of your local drugstore might be in order.

Seems inappropriate, doesn't it? After all, shouldn't our schools be teaching students to abstain from sex, rather than instructing them in the proper use of condoms?

If you answered yes, you're not alone.

According to a Zogby International poll taken last year, an overwhelming majority of parents want their children to hear a strong message of abstinence. Nearly 80 percent of parents want teens to be taught that they shouldn't engage in sex until they are married or at least in an adult relationship leading to marriage. And more than 90 percent say schools should teach teens "to abstain from sexual activity during high-school years."

Unfortunately, many schools aren't teaching abstinence. They're teaching something called "abstinence plus" or claiming their programs are "abstinence-based." It must be a case of new math, though, because the so-called "plus" actually subtracts from the abstinence message.

To prove that, analysts here at The Heritage Foundation recently completed a study comparing traditional abstinence programs with those known as abstinence-plus.

On average, authentic abstinence curricula devote more than half of their content to abstinence-related material. That is, information that encourages children to wait until they're married before they start having sex. In addition, these curricula use another 17 percent of their content to promote healthy relationships and to explain the benefits of marriage. Those messages both directly reinforce the main theme of teen abstinence.

But the "abstinence-plus" curricula take the opposite approach. On average, they devote less than 5 percent of their content to the topic of abstinence. And they do nothing to promote healthy relationships and marriage. Instead, these curricula focus on encouraging young people to use contraception.

The problem is that abstinence-plus curricula largely depict human sexuality as something that's merely a physical process. They focus on the physical body, not the whole person, and their predominant goal is to reduce the level of "unprotected" sexual activity by encouraging young people to use contraception. Thus, they teach students how to use condoms and coach them on how they can convince a resistant sex partner to use condoms.

After all that, any abstinence message that's tossed in is sure to get lost.

True abstinence programs, by contrast, address the student's whole person. They teach that sex has not just physical effects, but emotional, mental and psychological consequences, so students should wait until they're in a stable, adult relationship -- i.e., marriage -- to begin having sex. By waiting, they're guaranteed to avoid out-of-wedlock pregnancy, STDs and all the other risks of early sexual activity.

And this approach works. Study after study shows that genuine abstinence education reduces teen sexual activity. That's why it's especially upsetting that the government is spending roughly $12 promoting contraceptive use for every $1 it spends promoting abstinence.

Early sexual activity leads directly to many social problems. The rate of sexually transmitted disease infection among teens is increasing. Teen pregnancy and out-of-wedlock births remain significant problems. Plus, studies prove that teenaged sexual activity is linked to emotional problems and depression. There is also widespread concern that casual sexual activity at an early age can lead to unstable relationships and marital failure later in life.

Parents know all this instinctively and know that teaching our children to wait is the only way to avoid these problems. So, parents: Do you know which version of sex ed is being taught in your child's school this year? Is it the one that works, or the one that doesn't? Maybe it's time to find out.

Ed Feulner is president of The Heritage Foundation, a Washington-based public policy research institute.