Currently there is no vaccine for Zika (though one was just approved for clinical trials), and there is no treatment. When people talk about the response to the outbreak, they primarily talk about mosquito control and bug spray. One might think that medicine has no weapon to offer the average person to fight this disease right now. But that’s not true.

“We don’t know how to prevent Zika, but we do know how to prevent pregnancy,” says Christopher Zahn, the vice president of practice at The American College of Obstetricians and Gynecologists (ACOG).

Birth control can’t keep you from getting Zika, but Zika in adults is not that bad. You get a fever, joint pain, a rash, and red eyes (if you get symptoms at all, which most don’t). Some adults do come down with the autoimmune syndrome Guillain-Barré, but while the exact percentage isn’t known, the risk of getting it seems very low. It’s not the adults who need the most protection. The greatest risk is for children born to mothers who get Zika while pregnant—miscarriage and a range of birth defects, including microcephaly, are possible. (As of Thursday, seven babies have been born in the U.S. with Zika-related birth defects.)

“If effective contraception is provided and people use it, it’s theoretically 100 percent effective in prevention of those ultimate outcomes,” Zahn says. “The best way to avoid a potentially [affected] fetus is by avoiding pregnancy.”

In real life, there’s not perfect access to contraception, and there’s not perfect use of it. And Zika, it turns out, is both a mosquito-borne virus and a sexually-transmitted disease. The virus can live longer in semen than in blood—perhaps for months, though scientists don't know for sure—and be passed that way to a man’s sexual partners.

While mosquito control is still the most crucial way to slow this outbreak, there is some room for contraception to make a difference, both in preventing sexual transmission and in helping women delay pregnancy or avoid unintended pregnancies (and thus reduce the number of babies born with birth defects), whether they get it from a partner or a mosquito. For the best protection, experts say people need both condoms, to keep from spreading Zika sexually, and effective birth control, so even if a woman gets it anyway, there’s no fetus to worry about.

However, the Zika funding bill that was recently passed by the House of Representatives only to be rejected by the Senate included an explicit provision that none of the $1.1 billion it included could be put toward Planned Parenthood, and provided no other money for contraception.

“I think it's amazing for people to have been told the number-one thing they should and could do is delay pregnancy but we're going to give you no support or no means for doing that,” says Dawn Laguens, the executive vice president and chief experience officer at Planned Parenthood Federation of America.

“The contraceptive issue should not be avoided,” Zahn adds.

In the United States, 45 percent of all pregnancies are unintended. In Puerto Rico, where Zika is hitting hard, that rate is 65 percent. The Centers for Disease Control and Prevention recommends that couples trying to get pregnant wait six months to do so if a man gets infected and has symptoms, and wait eight weeks if a woman has symptoms. For people who’ve been traveling to areas with Zika, but didn’t get symptoms, the agency still recommends waiting eight weeks before trying to get pregnant. But if it’s accidental, well, those recommendations might not have been on the couple’s radar.

Places and populations that have insufficient access to and education about birth control are particularly at risk. “There is a substantial overlap between the areas at greatest risk for Zika virus spread [in the U.S.] and those populations with the poorest access to quality reproductive health services,” Jeffrey Klausner, a professor of medicine and public health at the University of California, Los Angeles, told me in an email. “Those are the areas and states in the Southeastern U.S. that border the Gulf of Mexico.” Puerto Rico is facing an access problem as well; in April the CDC estimated that “138,000 women of reproductive age in Puerto Rico do not desire pregnancy and are not using one of the most effective or moderately effective contraceptive methods.” Public health officials in Puerto Rico are also having trouble distributing donations of contraception that have been made, Reuters reports.

And as is so often the case with infectious disease, “the poor are going to get a double hit,” says Peter Hotez, the dean of the National School of Tropical Medicine at Baylor College of Medicine. “They’re at a greater risk of both modes of transmission.”

In some endemic areas, officials have advised people to just delay pregnancy. El Salvador, for example, has advised a wait of two years. The health secretary of Puerto Rico has promoted a delay, and as of early June, the World Health Organization has as well. The CDC has made no such recommendation, though Hotez thinks perhaps it should have.

“If you’re living in an area where there’s a high concentration of Aedes aegypti, think about delaying pregnancy this summer,” he says.

After this season, he thinks, the risk should go down, but if Zika goes the way of dengue and chikungunya, and lingers in affected regions, continuing to have seasonal flare-ups, the risk of birth defects won’t go away completely. For people who live in at-risk areas, Zika planning may become part of family planning for the foreseeable future.

“I believe that some kind of rapid testing will emerge and maybe become part of protocols around pregnancy,” Laguens says.

Because even if the U.S. Zika response gets funded with amazing provisions for contraception, even if access to contraception is improved, even if the Public Health gods snapped their fingers and got unintended pregnancy down to zero, it wouldn’t change the fact that some people want to get pregnant. And it’s not reasonable to expect everyone to wait until we totally understand the virus and its risks.

“The most important things that we should think about are: risk assessment, education, and decision-making between whoever’s providing reproductive health services and women and their partners,” says Kimberly Workowski, a professor of medicine at Emory University, who also consults for the CDC on STDs.

“It’s easy if someone doesn’t want to get pregnant, because we’ve got effective contraceptive methods,” Zahn says. “When somebody wants to get pregnant, and is planning that, you do the best you can do.”