Human Nature

Fetal Subtraction

Sex selection in the United States.

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A few weeks ago, I wrote about the transformation of sex selection—the practice of making sure your next baby isn’t of the “wrong” sex—into a consumer protection issue. We’re getting sufficiently used to this practice that we’ve begun to talk and write about whether companies that promote and facilitate it are delivering on their promises, rather than about whether what they’re doing is wrong.

One key point from that article was that the new transforms the old. What’s old is sex selection. What’s new is the combination of ease, safety, and privacy with which you can now do it. This is a fundamental dynamic between technology and culture: Technology can coax cultures one way or the other by making it easier to do what you want to do, with less difficulty and without other people knowing about it.

Now comes further evidence of this effect. Two days ago, economists Douglas Almond and Lena Edlund published an article in Proceedings of the National Academy of Sciences examining the ratio of male to female births in “U.S.-born childrenof Chinese, Korean, and Asian Indian parents.” Among whites, the boy-girl ratio was essentially constant, regardless of the number of kids in a family or how many of them were girls. In the Asian-American sample, the boy-girl ratio started out at the same norm: 1.05 to 1. But among families whose first child was a girl, the boy-girl ratio among second kids went up to 1.17 to 1. And if the first two kids were girls, the boy-girl ratio among third kids went up to 1.5 to 1. This 50 percent increase in male probability is directly contrary to the trend among whites, who tend to produce a child of the same sex as the previous child.

There’s no plausible innocent explanation for this enormous and directionally abnormal shift in probability. The authors conclude that the numbers are “evidence of sex selection, most likely atthe prenatal stage.”

Sex selection of this magnitude has previously been documented in China, South Korea, and India, but not in the United States. Here, the authors note, the usual economic and political rationales for sex selection—dowries, “patrilocal” marriage, China’s one-child policy, and dependence on your kids’ support in old age—don’t apply. From this absence of practical motive, some experts conclude that the study shows persistence of a cultural tradition as the populations in question migrated to the United States. But traditions can fade, and this one “is unlikely to persist in subsequent generations,” one demographer told the Associated Press.

If you look at sex selection as a cultural phenomenon, that may be true. But if you look at it as a technology, the opposite is just as plausible. The spread of fetal or embryonic sex-identification tests, which can be taken in the privacy of your home at increasingly early stages of pregnancy, makes it easier for sex selection to spread beyond its original cultural base. So does the emergence of pre-implantation genetic diagnosis, which lets you chuck your conceived offspring before pregnancy even begins.

In fact, the 2000 census data reviewed by Almond and Edlund suggest that within the base population, selection of male fetuses has indeed increased. “The male bias we find in the U.S. appears to be recent,” they write. “In the 1990 U.S. Census, the tendency for males to follow females among Indians, Chinese, and Koreans is substantially muted.”

The most obvious factor is technology. Referring to data from the U.S. National Center for Health Statistics, the authors observe, “Between 1989 and 1999, prenatal ultrasound use among non-Japanese Asian mothers rose from around 38 percent to 64 percent of pregnancies.” They add: “Since 2005, sexing through a blood test as early as 5 weeks after conception has been marketed directly to consumers in the U.S., raising the prospect of sex selection becoming more widely practiced in the near future.”

If you think of yourself as a techno-progressive—someone who believes, as Barack Obama does, that “maximizing the power of technology” will help fix everything from energy to the environment to health care—the increase in sex selection should give you pause. Technology can facilitate regression as easily as it facilitates progress. But if you think of yourself as a pro-life conservative, the data should humble you, too. In the populations in which it has increased, sex selection isn’t a newfangled perversion. It’s a custom, and a patriarchal one at that. If the sex-selection story teaches us all to be a bit more skeptical of both tradition and technology, that’ll be real progress.