Why ‘Genetic Testing’ for Gender Is Dangerous Pseudoscience

The theory suggested by the recent leaked U.S. Department of Health and Human Services memo is wrong about the science behind gender on two counts: gender identity likely has a neurological basis, and biological sex is not a strict binary.

[Photo: Athlete Dutee Chand stands at her podium draped in the Indian flag]
In 2014, India's Dutee Chand was forced to undergo a genitalia examination, a blood test, and a chromosome analysis that the track-and-field runner “found mortifying.” Lintao Zhang / Getty

On Sunday, the New York Times reported on a leaked memo from the U.S. Department of Health and Human Services that outlines a plan to define gender with regard to the Title IX civil rights law as, the Times summarized, “a biological, immutable condition determined by genitalia at birth.”

“The sex listed on a person’s birth certificate,” the memo reportedly read, “as originally issued, shall constitute definitive proof of a person’s sex unless rebutted by reliable genetic evidence.”

The New York Times didn’t explain what exactly the memo meant by “genetic evidence,” but it likely refers to a common argument from anti-trans conservatives: that chromosomes negate trans people’s identities. For example, in a debate on the talk show Dr. Drew on Call in 2015, Ben Shapiro of the conservative news site Daily Wire said, “It turns out that every chromosome, every cell in Caitlyn Jenner’s body, is male, with the exception of some of [her] sperm cells …. How [she] feels on the inside is irrelevant to the question of [her] biological self.” But this theory—and that is what’s suggested by the HHS memo—is wrong about the science behind gender on two counts: Gender identity likely has some kind of neurological basis, and biological sex is not a strict binary.

Several recent studies suggest that trans people’s brain patterns match their gender identities, regardless of genitalia. The most recent study was presented at the European Society of Endocrinology’s annual meeting in May. According to the press release, Dr. Julie Bakker of the University of Liège, Belgium, and her colleagues used MRIs to scan the brains of several transgender adolescents, specifically looking at reactions to “a pheromone known to produce gender-specific activity.” The researchers found that the brain patterns in the trans youth closely resembled their cisgender counterparts’. In other words, the research found that both cis and trans boys have some similar brain patterns, despite being born with different genitalia, and the same goes for both cis and trans girls. “Although more research is needed, we now have evidence that sexual differentiation of the brain differs in young people with [gender dysphoria],” says Dr. Bakker, “as they show functional brain characteristics that are typical of their desired gender.”

While not much is known about how gender identity develops, science does provide some clues. According to journalist Amy Ellis Nutt, author of the book Becoming Nicole: The Transformation of an American Family, gender identity development begins prenatally, and “many things can influence the environment of the womb, and the environment of the womb influences the level of hormones and the chemicals that go into the development of a fetus.”

Professor Dick F. Swaab of the Netherlands Institute for Neuroscience elaborates on this in his 2007 paper “Sexual differentiation of the brain and behavior.” He writes, “Different brain structures that result from interaction between hormones and developing brain cells are thought to be the basis of sex differences in the structure of the brain, and thus of behavior, gender identity, gender role, sexual orientation, and sex differences regarding cognition and aggression.” In other words, it appears likely that trans people are—in the immortal words of Lady Gaga—born this way.

As far as biological sex, science suggests there is no strict binary of male and female. For starters, as many as 1.7 percent of the general population is intersex, which the Intersex Society of North America defines as “a general term used for a variety of conditions in which a person is born with a reproductive or sexual anatomy that doesn’t seem to fit the typical definitions of female or male.” In other words, to name a few possibilities, some people have elements of both typically “male” and typically “female” genitalia; some may have internal anatomy that doesn’t correspond with typical external anatomy; and some have both XX and XY chromosomes. In fact, according to a 2015 article in Nature, science is starting to reveal that “almost everyone is, to varying degrees, a patchwork of genetically distinct cells, some with a sex that might not match that of the rest of their body.” For example, most biologists classify the “typical male” as one who has XY chromosomes, a penis, and external gonads. However, some have lower sperm count than others, some have anatomical variations with their penises, and some people with the 46,XY disorders of sexual development have ambiguous genitalia. The Nature article continues, “Some researchers now say that as many as 1 person in 100 has some form of” difference in sexual development.

And while the idea of genetic testing to determine gender is at this point just a hypothetical, it is not all that far-fetched given the history of invasive biological sex examinations in the world of athletics. Based on rumors that sprinter Helen Stephens was a “man pretending to be a woman” in order to win the women’s 100-meter sprint, the 1936 Olympics committee gave her “a crude physical examination involving the gross inspection of the external genitalia.” By the 1960s, female athletes competing at international games had to stand naked before a panel of doctors to prove they were “biologically female.” These inspections cost sisters Irina and Tamara Press their careers; despite having five Olympic gold medals between them, the two refused to undergo sex inspection before the 1966 European championships, and they never competed again.

Genetic testing was introduced to athletics in the late 1960s, but it was no less invasive and humiliating for many who underwent the procedure. In 2014, India’s Dutee Chand was forced to undergo a genitalia examination, a blood test, and a chromosome analysis that the track-and-field runner “found mortifying.” The tests found that her body produced a rather high amount of testosterone for an average woman, and she was disqualified from participating in future competitions. Fortunately, Chand was allowed to compete again, following revised regulations from the IAAF. (As ESPN notes, “There is no clarity on whether the IAAF was able to find scientific evidence proving competitive advantage of female athletes with high levels of testosterone.”)

If these genetic tests were able to disrupt or ruin the careers of athletes with variant chromosomes, or the careers of athletes who produce high amounts of sex hormones not typically associated with their assigned gender at birth, it’s easy to imagine what would happen if the U.S. government implemented genetic testing to determine whether or not an individual’s civil rights should be covered under Title IX.

If these proposed changes come to pass, the New York Times says they would “essentially eradicate federal recognition of the estimated 1.4 million Americans who have opted to recognize themselves—surgically or otherwise—as a gender other than the one they were born into.” Not only that, but the resolution’s flawed understanding of chromosomes and genetics could worsen discrimination against intersex people, many of whom are also trans.

And even if the science behind genetic testing for the “correct” gender was solid, why would it matter? If you need a peer-reviewed science journal article to affirm the inherent worth and dignity of another human being, you might need to get your priorities straight.