Debunked: The Transgender 'Brain Sex' Argument

The notion that “gender identity” is brain-based and innate has captured the political left. This article explains how to debunk transgender "brain sex" conjecture.

Image by Milad Fakurian

This article has been updated with a new introduction to provide further context as to why the “brain sex” theory is central to the debate over transgender issues.

Why do progressives and gender activists fervently believe that “transgender” women are literally women? Why do they believe in the existence of “transgender children” that must be medically transitioned to avoid going through the “wrong puberty”? Why is “gender identity” taking precedence over biological sex in legislation like Title IX? How can they confidently assert that “the science” is on their side?

The answer to all of these questions is due to the belief that being transgender is an innate biological property of human beings. The notion that “gender identity” is brain-based and innate has captured the political left. This is due to a collection of brain studies that purport to show that people who identify as transgender have brain structures that are more similar to the sex with which they “identify” than to their actual sex. Widespread media coverage of these studies lauds them as “proof” that transgender people “are who they say they are.”

Progressive media outlets have glommed onto this narrative and published dozens of articles asserting that “transgender people are born that way” and that “science proves trans people aren’t making it up.” Mainstream media like CNN, the New York Times, Newsweek, the Telegraph and scientific sources like Nature, National Geographic, the Cleveland Clinic and Scientific American have also repeated this misinformation.

To make matters worse, the “brain sex” conjecture is baked into clinical guidelines for medical transition and legislation for employment, healthcare, and education. 

The transgender “brain sex” argument is a load-bearing pillar supporting the belief that people are born transgender and should therefore medically transition as early as possible. Several female detransitioners who were medically transitioned as minors have even discussed how their doctors wrongly informed them that they possessed "a male brain in a female body." This claim is so absurd you’d wonder how the average person, let alone a medical doctor, would believe it.

One major player responsible for perpetuating this myth is Dr. Joshua Safer, an endocrinologist and the executive director of the Mount Sinai Center for Transgender Medicine and Surgery in New York City. Safer is a leading advocate of  "gender affirming care" and believes that "gender identity" is biologically determined. A review article he published on the topic relies heavily on brain studies and disorders of sexual development (which are often used to argue that the sex binary should be represented as a spectrum).

 A 2016 interview with WBUR gives insights into how the “brain sex” theory shifted Safer’s perspective of the transgender experience from a mental health issue to a medical one.

"Up until a decade or so ago, the view among many providers was that this was probably a mental disorder and the fear was that doing hormone therapy or doing surgery might be abetting a mental disorder and the correct intervention would be to counsel people," Safer said. 

But Safer's research traces the increasing evidence that gender identity is rooted in biology, "which makes it so logical that an option for people in 2016 is to change the external appearance to meet that gender identity," he said. 

Why does it matter? Because Dr. Safer is currently the co-chair of the World Professional Association for Transgender Health (WPATH) and has been involved with the organization for many years, including serving as the first president of USPATH, the United States affiliate of WPATH. Most importantly, he co-authored two sets of clinical guidelines for the medical care of transgender patients: the WPATH's Standards of Care and the Endocrine Society guidelines. These guidelines are considered the gold standard in gender medicine and are used by gender clinics worldwide.

Dr. Safer has testified in numerous legal cases related to "transgender rights," providing expert testimony on the purportedly scientific aspects of “gender identity,” particularly as it relates to "brain sex." He appeared on a panel with comedian Jon Stewart last year and has discussed the concept of "brain sex" in various media outlets, including the New York Times and a PBS documentary.

The assumption that being transgender is an innate property that can be detected by brain scans is central to all of the problems we see today surrounding transgender issues. It is therefore crucial to be aware of and challenge the transgender “brain sex” argument whenever it arises.

The “brain sex” argument

The “brain sex” argument claims that transgender people have regions in the brain that structurally resemble that of the opposite sex. This assertion is based on a number of studies conducted in recent years on people who identify as transgender to gain insight into the potential biological basis of their condition. Some studies have even purported to show that the brain structure of transgender individuals more closely resembles the sex they “identify” as than their natal sex.

The "brain sex" argument is based on the idea that there are differences in brain structure and function between males and females that are influenced by hormones and genetic factors. Advocates of this argument argue that these differences can also be seen in the brains of transgender individuals and that these differences may contribute to the development of a “gender identity” that is different from their natal sex. They believe that a biological male who identifies as a woman has brain structures that more closely resemble that of typical females, and vice versa.

Here’s why it's wrong 

The majority of the studies on the “transgender brain” have a fatal flaw: they didn’t control for confounding variables like cross-sex hormone use and, most importantly, sexual orientation. When a study doesn't control for confounding variables, it means that the researchers did not take into account other factors that could have affected the results of the study, which make it difficult or impossible to determine whether the relationship between the two variables being studied is truly causal or a byproduct of other unrelated factors.

Cross-sex hormone use can have effects on the brain, including changes in brain structure and function. But more importantly, many trans-identifying individuals are same-sex attracted, so the research on the “transgender brain” claiming to find structural regions that resemble the opposite sex are essentially rediscovering findings on the “gay brain” and reinterpreting the results to fit their preferred conclusion. 

In the early nineties, neuroscientist and author Simon LeVay made the breakthrough discovery that the brains of homosexuals had structural differences that resembled that of straight members of the opposite sex. So it seems that while undertaking the hunt for the “transgender brain,” researchers have forgotten all about the discoveries made about the brains of same-sex attracted people. 

The first “brain sex” study that did take into account the participants' sexual orientation found that the brains of transgender individuals were similar to those of people of the same birth sex rather than the opposite sex.

When researchers scan the brains of heterosexual people who identify as transgender, they also find they are typical for their natal sex. Samuel Stagg, a U.K.-based Ph.D. student of neuroimmunology, explains: “The homosexual sub-group show brains skewed along the male-female dimension. However, this is predominantly due to their co-occurring homosexuality. When we scan the brains of the heterosexual type, we find they are more typical for their natal sex.” 

“Gender identity” not gender dysphoria

Gender dysphoria, like other psychiatric conditions, may have some biological underpinnings. There are traits like neuroticism that can predispose people to psychiatric conditions and research suggests that neuroticism has a strong biological basis with both genetic and environmental factors contributing to its development. 

But gender activists are not concerned with gender dysphoria, rather they aim to establish a biological basis for being transgender that ceases to categorize it as a mental illness. Activists have pushed for a more “inclusive” definition of what it means to be transgender that seeks to reduce stigma and perceived barriers to medical transition services.

After the legalization of same-sex marriage in 2015, civil rights and gay rights organizations that may have otherwise had to shutter their doors pivoted to championing “trans rights.” The success of the "born this way" campaign in promoting the idea that sexual orientation is an innate, immutable aspect of identity has prompted activists to also present being transgender as innate and immutable.

Manhattan Institute fellow Leor Sapir wrote his Ph.D. dissertation on the rapid proliferation of the “transgender rights movement” and its efforts to obtain civil rights jurisprudence for “gender identity.” To this end, they have attempted to prove that “gender identity” is an innate, immutable trait called “neurological sex” or “brain sex,” which they say should override natal sex.

“In the American civil rights tradition, if you can convince a judge that being transgender is like being black, then you can tap into this entire body of judicial precedent and civil rights laws that immediately applies and gives you all the policies you want,” Sapir told me. Leor Sapir has written a number of important articles on this topic for City Journal, be sure to read them for further understanding.

More context: the trans community is divided

Interestingly, on the surface the transgender community presents as a unified front, but in reality it is divided into opposing philosophical factions: those propelled by civil rights organizations who seek to prove that being transgender is an “innate, immutable trait” for political and legal reasons, and the queer theorists who question the basis of scientific authority. 

Last December, a transgender rights organization announced they were publishing a “groundbreaking article” that claims “being trans is a biological condition.” But after hundreds of critical comments from transgender people claiming that the search to find a biological basis for being transgender could be exploited, citing “eugenics” as a top concern, the organization spiked the article and issued an apology.

A self-described queer theorist named Eirnin who had early access to the article said it was not peer-reviewed nor written by an expert in the field but was merely a short letter that combined several theories of “brain sex” based on “debunked science.”

Another key point 

If “gender identity” were solely biologically ingrained, it would conflict with the fact that gender dysphoria has been observed to resolve spontaneously or through psychotherapy at various ages. As we know from the growing population of detransitioners and a large body of research on desistance in children, transgender identities are not necessarily fixed. Currently, there is no brain, blood, or other objective test that distinguishes a trans-identified from a non-trans identified person.

Group project

This article is intentionally simplified to convey the main points effectively. It is my hope that it will assist individuals in countering the transgender "brain sex" argument when they encounter it. However, I am collaborating with neuroscientist Sammy Stagg on a group project to publish a paper that highlights the methodological flaws present in current "brain sex" research in a more comprehensive way.

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