Two years into their relationship, Caroline and her husband, Deon, began talking about having a baby. It’s a big decision for any couple, but in an era when same-sex couples have come under fire for raising kids and women face ever-tighter restrictions on their reproductive choices, little seems less controversial than a heterosexual couple starting a family. But Deon is HIV-positive—and the Watsons are one of an increasing number of so-called serodiscordant couples taking the plunge.

Caroline found out about Deon’s HIV status through a mutual friend before they began dating, so she knew what she was getting into. “I fell in love with him anyway,” she says. Deon began taking antiretroviral drugs—that cocktail of medications that keep the virus at bay and boost regular immune function—about six months after the couple connected. It wasn’t long before HIV became undetectable in his system.

Caroline also knew that several recent studies of serodiscordant couples showed that the risk of transmitting HIV from an infected partner is essentially zero if his or her viral load is undetectable. Caroline had done her homework before they started talking baby. “I wasn’t concerned about transmission,” she says.

Their daughter, Valerie, was born in the spring of 2013. Caroline had a largely uneventful pregnancy, and Valerie is big, strong and healthy. Both she and Caroline remain HIV-negative.

Author and journalist Heather Boerner followed the conception choices of serodiscordant couples like the Watsons for her new longform piece, Positively Negative: Love, Pregnancy, and Science’s Surprising Triumph Over HIV. Boerner came of age in the 1980s, when HIV’s mysterious emergence frightened a generation—most of whom came to believe that hooking up with an HIV-positive partner was a death sentence.

Talking to the couples for Positively Negative, “my head kind of exploded,” Boerner says. “I knew HIV had changed, but it had never occurred to me that it had changed so much.”

Today, more than 1.1 million Americans are living with HIV, according to the Centers for Disease Control. CDC data suggests that there are at least 140,000 serodiscordant couples in the United States. Roughly half of those would like to have children, according to Shannon Weber, the coordinator for the Bay Area Perinatal AIDS Center at the University of California at San Francisco (BAPAC).

Although there isn’t good data on how many of those couples include HIV-positive men, roughly 8,000 to 9,000 HIV-positive women give birth each year, and only 150 of their babies—less than 1.6 percent—contract HIV. Many HIV-positive infants are the products of unplanned pregnancies, meaning their parents might not have taken antiretrovirals or other steps to protect themselves and their fetuses from the virus, Weber says.

Gilead’s antiretroviral drug Truvada, along with generic forms, are prescribed to HIV-negative sex partners of HIV-positive men and women to provide an extra layer of protection against contracting the virus. Used in this way, medications like Truvada are referred to as pre-exposure prophylaxis, or PrEP, and are taken throughout the planned conception period. It takes about 20 days to build up in the vaginal fluids, so women must continue taking it until they get that positive pregnancy test and resume using condoms, Boerner says.

Although HIV doctors have been familiar with PrEP for years, it’s taken almost a decade for that information to break through to the non-HIV medical community, according to Boerner. That’s one reason she wrote Positively Negative. “This is the result of the siloing of HIV care,” she says. “I wanted people to be aware, and I wanted non-HIV doctors to know it’s possible and it’s safe.”

The U.S. Food and Drug Administration approved Truvada for PrEP—for men and women—in July of 2012. Between January of 2012 and September of 2013, 2,319 patients began taking Truvada prophylactically, and more than half of those were women, according to information provided by Gilead.

Some women, such as Watson, opt not to use PrEP. “I was concerned about what it could do to the baby; there weren’t enough studies done on pregnant women taking PrEP for me to feel safe doing it, especially considering the next-to-zero chance of me becoming infected,” she says.

In recent months, the American Congress of Obstetricians and Gynecologists and the CDC have developed recommendations for doctors with patients in serodiscordant couples who are trying to conceive, with a particular focus on PrEP. Those developments should open the door for more couples to become aware that it’s safe for them to have children together.<

As the medical community has become more open to the possibility of serodiscordant couples having children, BAPAC is seeing more demand for its services. Although the clinic takes on just a small number of families a year, it’s no longer the only center of its type, Weber says. Now there are other facilities helping these couples navigate the world of research and medication surrounding their choice to have unprotected sex in the pursuit of raising a family, including sites at Boston University, Johns Hopkins University and Drexel University, all of whom will be working together over the next year in a Gilead-funded study looking at the use of PrEP in HIV-negative women having children with HIV-positive men, Weber says.

“Going by the requests we’ve gotten, and the new CDC guidelines are very supportive, I anticipate there’s going to be more couples trying,” Weber says. Although BAPAC started out primarily working with HIV-positive women who wanted to find ways to prevent passing the virus to their children, “probably half the couples we see now are HIV-negative women with positive partners.”

However, there’s still plenty of stigma surrounding HIV, an issue that prevented some couples from sharing their stories with Boerner. Others only agreed to appear under pseudonyms. That didn’t keep Boerner from wanting to bring to light their conception journeys—or the journeys of doctors who coached them before these methods were adopted by the larger community.

“It’s important to chronicle the pioneers in the process. The cloud of silence they operate under is not that different from what the couples experience,” Boerner says. “I wanted to recognize how brave these couples are—and the researchers.”