The American Academy of Pediatrics has just revised its official position on birth control: The academy's new guidence advises members to recommend intrauterine devices (IUDs) and progestin implants as the most effective birth control methods available. The announcement, which appears in the flagship journal Pediatrics, is important for its own sake— because it’s likely to change patterns of medical practice—and reduce the incidence of pregnancy. It’s also important for what it says about the ongoing controversy over who should pay for contraception.

IUDs come in two forms, one that uses copper and another that uses hormones. With either one, a physician implants the device in the uterus and it lasts for years. Both pediatricians and gynecologists like IUDs because they are just as effective in real-life as they are in the lab. By contrast, the two most popular contraceptives for teens, condoms and the pill, are more prone to human error. Women on the pill may miss a dose or partners may incorrectly use a condom. Women can still unexpectedly become pregnant between 18 and 21 percent of the time when using condoms, or 9 percent of the time while on the pill. For the IUD, the pregnancy rate is less than 1 percent:

IUD usage in the U.S. is still fairly rare in the United States, especially among teens (just 3 percent of teens rely on IUDs). But that is finally changing, rising from just 2 percent to 8.5 percent between 2002-2009. One likely reason that may continue to change is, under the Affordable Care Act, all insurance policies must cover birth control fully, without extra out-of-pocket costs. Implanting an IUD is expensive—it can run several hundred dollars, without insurance—so the coverage makes a difference.

Some conservatives might bristle at the idea of pediatricians counseling teens about sex. But the new guidelines make clear that “Adolescents should be encouraged to delay sexual onset until they are ready.” The problem, the article explains, is that "existing data suggest that, over time, perfect adherence to abstinence is low (i.e., many adolescents planning on abstinence do not remain abstinent).”

Insurance coverage of IUDs is another matter, one that’s been in the news a lot lately. Conservatives say it’s a form of “abortifacient,” because, they argue, it can prevent a fertilized egg from implanting in the uterus. An Ohio legislator this summer introduced a bill this summer to strip health coverage of IUDs from insurance plans in the state, for example, and religious groups cited this argument in their case against the Affordable Care Act’s contraception mandate—an objection that the Supreme Court recognized in the Hobby Lobby case.

But conservatives are making specious scientific claims, as obstetrician Jen Gunter has noted at Q.E.D. And even putting those asides, this new study is a reminder of why payment for the IUD matters in the first place. It’s not enough to note that birth control pills are cheap or suggest they be made available over-the-counter, as some conservatives now suggest. Doctors recognize that not all birth control methods are equal.