There’s a Reason Scientists Keep Talking About Race and Sex

(Bloomberg Opinion) -- The scientific understanding of race and sex hasn't changed much in recent years, and yet people are confused. It's hard to escape promotions for DNA tests promising to reveal your true identity in the form of a percentage breakdown of groups that used to be called races. Now what are they?

Then, last week, the media presented a Trump administration memo proclaiming that “Sex means a person's status as male or female based on immutable biological traits identifiable by or before birth…” and in response, the New York Times ran an op-ed explaining why sex is not binary.

It's not surprising that some people would wonder if science is being distorted by political correctness. Here, in a letter posted in the Wall Street Journal last week, someone asked if the political left was denying biology:

If race isn't a measurable biological category, was Sen. Warren justified in identifying herself as Native American because she believed she was? … Now the left argues that sexual identity is something everyone can choose and change as preferences change.

I myself have written about the nonbinary nature of sex, and in earlier columns, about why nature gave us (as we see it) two sexes (basically). Some mushrooms mate through a system of thousands of sexes, but that's a story for another time. The question at hand is whether I've contradicted myself.

Biologist Jerry Coyne explained on his blog that what determines maleness and femaleness is a complex series of steps involving multiple genes and hormones. Usually, the end result is that a person's gonads, chromosomes and hormones line up into the categories we invented, male or female.

By “usually” isn't always. Some people have a Y chromosome and a female-looking body, or they are born with ambiguous genitalia, or their body has male traits but they identify as a woman. Sex is real, but it isn't a strict either-or.

My past writings on race might also look self-contradictory, as I've stated that modern genetics has proven there's no biological basis for dividing people into races. But in earlier stories I've written on health disparities that put African Americans at increased risk of certain kinds of cancer. Are scientists just calling race something else for political reasons?

It's a question that geneticist Joseph Graves tackled in his article “If Race Is a Social Construct, What's Up With DNA Ancestry Testing?” He reiterates that we all share recent common ancestors, and that we all come from Africa. There are variations: Some people have different skin colors, some people can digest lactose and some people are more likely to carry the sickle cell gene. The distribution of those traits clusters around certain geographic regions. The traits are real, but society decides how to divide humanity into categories, or whether to categorize ourselves at all.

Despite the debunking of human races, scientists continue to categorize people in a way that sounds a lot like race, often substituting the term “population.” But this too, is artificial, argued Field Museum anthropologist John Edward Terrell. Scientists make up categories like this all the time; most of biology was categorization in the decades before Darwin. Scientists have had to rethink how to categorize planets once they found the solar system held dozens of objects that were comparable to or bigger than Pluto. As anthropologist Robert Sapolksy wrote in Nautilus Magazine last year, the human mind sees the world in categories.

Scientists aren't supposed to make up data, but they can make up categories if these serve some purpose in helping make sense of the world. That would be the case for doctors who need to use race or population labels to make the best recommendations for cancer screenings or treatments, or ones who are trying to understand what environmental or genetic factors are causing disparities.

The Wall Street Journal letter writer expressed concern that people are making choices about their own race or sex that violate immutable categories. Terrell is worried about a different kind of choice — the choices scientists make in imposing categories on humanity, sometimes to help them in their research, and sometimes to sell more DNA ancestry tests. He's worried that scientists are failing to remind people that these categories like “male” and “white” are completely invented by humans. Any scientific discourse that mentions race or sex should come with a warning label: “for bookkeeping purposes only.”

To contact the editor responsible for this story: Philip Gray at philipgray@bloomberg.net

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Faye Flam is a Bloomberg Opinion columnist. She has written for the Economist, the New York Times, the Washington Post, Psychology Today, Science and other publications. She has a degree in geophysics from the California Institute of Technology.

©2018 Bloomberg L.P.