Rep. Trent Franks (R-Ariz.) has sponsored legislation that would ban abortions based on gender. (Matt York/AP)

There’s a lot of debate over what this bill would mean for women’s health. Reproductive health advocates have called it “a sneak attack” on abortion access, arguing that the consequences could deter doctors from performing a legal, medical procedure. The American College of Obstetricians and Gynecologists, which instructs its members not to perform sex-selective abortions, opposes this specific bill because it could deter access.

Underlying this fight, however, is a more basic question: Are sex-selective abortions actually happening in the United States? If so, to what extent? While researchers haven’t found evidence of these types of abortion being widespread, some have located instances of cultural forces pushing some women to end pregnancies because of the gender of their fetus.

The introduction of ultrasound and amniocentesis technology in the 1970s made it possible to determine the gender of a fetus as early as the 14th week of pregnancy. In some Asian countries, where a higher value is placed on having a son, researchers have found that sex-selective terminations of female fetuses became “common” as early as the mid-1990s. In China, 117 boys are born for every 100 girls, according to 2011 statistics.

The United States, by contrast, has a more balanced gender ratio for its births. Right now, 105 boys are born for every 100 girls, a ratio that the Center for Disease Control says has remained “remarkably stable” since the 1940s. It’s also worth noting that 91.5 percent of abortions are performed prior to 13 weeks of pregnancy, before gender can be determined.

Some studies have looked specifically at immigrant communities, from countries where sex-selective abortion does seem to be prevalent, to see whether similar abortions happen in the United States.

Jason Abrevaya, an economist at the University of Texas, studied census data of birth rates for Asian Americans. He did find, in a 2008 paper, some indications of a preference for sons: Asian immigrant families that had two daughters were more likely to become pregnant with a third child, compared to those that already had a son. But what Abrevaya didn’t see was any skewed gender ratios among the births of third children; the birth ratios between girls and boys were the same as for prior births. That indicated that it was unlikely that sex-selective abortion was occurring.

“The empirical results do not provide much evidence of unusual boy-birth percentages that would suggest that gender selection is being used to achieve a gender mix,” he concluded.

This does not mean such abortions do not occur: A smaller study from the University of California-Irvine focused specifically on 65 Indian American women who said they did have a sex-selective abortion. Many of those women identified pressure from both female in-laws and husbands to have male children, underlied by cultural gender inequalities.

“My first child is a girl,” one woman told the researchers. “My mother-in-law said that is okay, she said at least it is good that I can have babies. But when my second child was also a girl, she did not want to hold her after the birth. She yelled at me that I should have had this test to know if I had a boy or girl.”

The lead researcher, Sunita Puri, argues in a separate piece on her study that ultrasounds and doctors aren’t necessarily to blame for sex-selective abortion. “Technology or physicians alone are not at the root of the problem,” she writes. “The use of technology and marketing of sex selection exist because of the preference for a male child.”

While her research has often been invoked by supporters of the Franks bill, Puri herself has never endorsed a policy like the one Congress is debating (I reached out to her for an interview on the subject, but she was unavailable as of deadline). In writing, though, she has advocated for making cultural changes that elevate the position of women, such as “congratulating couples equally when sons and daughters are born” or “more days to celebrate women’s many accomplishments.” To combat sex-selective abortions, Puri contends, “We can remind our daughters every day that they are equal to their brothers in every way.”