Every two years, the Centers for Disease Control and Prevention’s Division of Adolescent and School Health (CDC-DASH) surveys high school students to gauge how often they engage in perceived risky behaviors. The national Youth Risk Behavior Surveillance (YRBS) is wide ranging: It asks about violence, guns, alcohol, drugs, seat belts, bicycle safety, and nutrition. It also asks questions about “sexual intercourse” (which it doesn’t define as a specific act) and sexual behaviors.

Started in 1991, this long-running study can provide both a picture of what high school students are doing right now and a historical perspective of how things have changed. But for more than a decade, the story it has told about sexual risk has been the virtually the same. Risk behaviors continually declined between 1991 and 2001, with fewer high school students having sex and more of them using condoms and contraception. But after the first 10 years, there has been little change in youth sexual risk behaviors. And, with each new release of almost unchanging data, I’ve reminded us that no news isn’t necessarily good news.

This year, there is news and it looks good—at least on the surface. The survey showed some significant changes between 2013 and 2015; fewer kids have ever had sex, are currently sexually active, or became sexually active at a young age. More teens are relying on IUDs and implants, which are virtually error-proof in preventing pregnancy.

In 2015, 41 percent of high school students reported ever having had sexual intercourse compared to 47 percent in 2013. The researchers say this is a statistically significant decrease, which adds to the decreases seen since 1991, when 54 percent of teens reported ever having had sexual intercourse.

Another change is in the percentage of students who had sex for the first time before age 13. In 2015, 4 percent of high school students reported this compared to almost 6 percent in 2013. This is down from a full 10 percent in 1991. As for number of overall partners, that is down as well, with only 12 percent of students reporting four or more partners during their lifetime compared to 15 percent in 2013 and 19 percent in 1991. Finally, the percentage of students who are currently sexually active also decreased significantly between 2013 (34 percent) and 2015 (30 percent).

These are all positive developments. Delaying sex can often help prevent (at least temporarily) the risk of pregnancy or STIs. Having fewer partners, especially fewer concurrent partners, is frequently important for reducing STI risk. And those teens who are not currently having sex are not currently at risk for those things.

While I want to congratulate all teens who took fewer risks this year, I’m not ready to celebrate those statistics alone—because the number of teens having sex is less important to me than the percentage of teens having sex that is protected from both pregnancy and sexually transmitted infections. And that number is lower than it once was.

Among sexually active teens, there were no significant positive changes in measures of safer sex other than an increase in the number of sexually active high school students using the IUD or implant (up to 4 percent from 2 percent in 2013).

Moreover, some results indicate that today’s teens are using less protection than those who were teens a decade ago. The most telling finding might be the percentage of teens who used no method of contraception the last time they had sex. This decreased between 1991 and 2007 (from 17 percent to 12 percent), inched up to 14 percent in 2013, and stayed the same in 2015 (14 percent). There was also little to no change in the percentage of high school students who say that either they or their partner used birth control pills between 2013 (19 percent) and 2015 (18 percent) or those who say they used the contraceptive shot, patch, or ring (5 percent in 2013 and 2015).

For me, however, the most distressing finding is the backward progress we continue to see in condom use. The prevalence of high school students who used a condom at last sex went up from 45 percent in 1991 to 63 percent in 2003. But then it started to drop. In 2015, only 57 percent of sexually active high school students used condoms the last time they had sex, less than in 2013, when 59 percent said they used condoms.

It’s not surprising that teens use condoms less frequently than they did a decade ago. In the 1990s, the HIV epidemic was still front and center, and condoms were heavily promoted as a way to avoid infection. As this threat waned—thanks to treatment advances that now also serve as prevention—discussions of the importance of condoms diminished as well. The rise of abstinence-only-until-marriage programs may have also affected condom use, because these programs often include misinformation suggesting condoms are unreliable at best.

Unfortunately, some of the negative messages about condoms inadvertently came from public health experts themselves, whether they were promoting emergency contraception with ads that said “oops, the condom broke”; encouraging the development of new condoms with articles suggesting that current condoms are no fun; or focusing on teen pregnancy and the use of highly effective contraceptive methods such as long-acting reversible contraceptives (LARC). The end result is that condoms have been undersold to today’s teenagers.

We have to turn these condom trends around, because despite the decreases in sexual activity, young people continue to contract STIs at an alarming rate. In 2014, for example, there were nearly 950,000 reported cases of chlamydia among young people ages 15 to 24. In fact, young people in this age group represented 66 percent of all reported chlamydia cases. Similarly, in 2014, young women ages 15 to 19 had the second-highest rate of gonorrhea infection of any age group (400 cases per 100,000 women in the age group), exceeded only by those 20 to 24 (489 cases per 100,000 women).

While we can be pleased that fewer young people are having sex right now, we can’t fool ourselves into believing that this is enough or that our prevention messages are truly working. We should certainly praise teens for taking fewer risks and use this survey as a reminder that teens can and do make good decisions. But while we’re shaking a young person’s hand, we should be slipping a condom into it. Because someday soon (before high school ends, for more than half of them), that teenager will have sex—and when they do, they need to protect themselves from both pregnancy and STIs.