What Science Can Tell Us About Trans People’s Brains—And What It Cannot

A study has shown that trans people may sense touch differently than cisgender people according to particular body parts. We should be curious, but also careful, what we extrapolate from such findings.

What does gender dysphoria feel like?

For those who are not transgender themselves—and, in the United States, that’s all but 1.4 million of us—the idea of our actual gender not matching the one we were assigned at birth might seem foreign or, worse, far-fetched.

But gender dysphoria is a real psychiatric diagnosis with proven treatments that are supported by most major medical associations. And a small but nascent body of research is beginning to examine how it feels—from the surface of the skin to the depths of the brain—to need to transition from one gender to another.The science is not yet fully-formed and the sample sizes are tiny, but the handful of studies in this area would be informative for anyone still clinging to the idea that transgender people are just “making it up.”

“Certainly we can say more than ‘people say they feel this’ or ‘people feel this,’ we can say that it’s in their brain, it’s a rapid sensory response, and there’s a strong argument that it’s automatic,” neuroscientist Dr. Laura Case told The Daily Beast.

When Case, now a postdoctoral fellow at the National Center for Complementary and Integrative Health, was completing her degree in experimental psychology at the University of California, San Diego, she and a small research team conducted an experiment on eight transgender men and genderqueer individuals who had not yet received a double mastectomy to remove their breasts, but who wanted to do so.

At its heart, the experiment was simple: a research assistant used a small piece of tapered plastic to consensually tap the subjects on their hands and then on their upper breasts through a shirt.

The assistant also tapped eight cisgender, or non-transgender, women in these same locations using the same timing and technique. But while the subjects were being tapped, their brain activity was also being recorded in detail by complex neuroimaging machinery in the UCSD lab.

The finished study, published in the Archives of Sexual Behavior late last year had some striking results: When tapped on their upper breasts, the transgender and male-leaning genderqueer subjects had a reduced response in brain areas that are thought to make “self-other” distinctions—a response that was “rapid and automatic at the sensory level.”

In other words, Case may have captured gender dysphoria in motion down to the millisecond.

“You could sort of call this an objective or physiologic measure,” she told The Daily Beast.

Notably, the brains of the cisgender women and the brains of the experimental group behaved similarly when processing the taps on the hand. But the two sets of subjects had divergent brain responses when they were tapped on a body part that one group wanted to keep and the other wanted to remove surgically.

The transgender and genderqueer individuals, in particular, displayed brain activity that suggested “less integration and more anxiety and alarm for sensation from this body part.” Case believes that this brain response reflects and reaffirms that group’s subjective feeling that “the breast is not a natural part of their body or doesn’t fit with their body image.”

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“The brain is not identifying this sensation as ‘me’ as much as it is other parts of the body—and it’s alarmed by it,” she told The Daily Beast. “That’s our read of it.”

Of course, there’s a chicken-or-the-egg problem here: Is gender dysphoria the result of this difference in brain response or is it the cause? Can the brain explain how someone becomes transgender, or does being transgender explain how the brain behaves?

Case can’t make any firm conclusions either way. As she notes in the study, “Scientific reductionism is unlikely to yield a simple explanation for a phenomenon as complex as gender identity.” As they did with homosexuality, researchers have tried and failed to conclusively identify biological indicators—and even causes of—transgender identity.

But Case still finds the results of her experiment suggestive as an in-the-moment look at the phenomenon of gender dysphoria in the brain.

“I think it validates [their] experience and it additionally suggests that it’s fairly automatic,” said Case of her transgender and genderqueer subjects. “Whether that’s because of how the brain is developed or is connected, or if it’s a buildup of life experience that’s reshaped how that information is processed, I really can’t say.”

Case’s work in this area builds on a potential avenue of research opened up by her dissertation adviser, Dr. Vilayanur Ramachandran, a famous neuroscientist and author currently working at UCSD. Ramachandran’s work is eclectic, interdisciplinary, and sometimes controversial, touching on subjects ranging from synesthesia to autism.

In the late 2000s, he and UCSD colleague Dr. Paul McGeoch published two fairly speculative papers examining the parallels between transgender people’s bodily experiences and another one of Ramachandran’s favorite areas: “phantom limb,” the fairly common sensation that a body part is still there after it has been amputated.

Interestingly, some transgender people say they experience “phantom limb” sensations about body parts they do not yet possess. On transgender web forums, for example, it’s easy to find transgender men who describe experiencing “phantom penis” sensations. Some transgender women report similar feelings about other body parts.

“That’s what clued us in,” Ramachandran told The Daily Beast, recalling the first time he heard about these anecdotal reports. “It’s quite common. And people [other researchers] no doubt knew about it and ignored it—or decided it was spooky or weird or just psychological wish fulfillment.”

Ramachandran decided to look a little deeper instead of dismissing the claims outright.

In the first paper, published in the speculative journal Medical Hypotheses, intended to be a forum for “novel, radical ideas,” he and McGeoch hypothesized that transgender women who had undergone sex reassignment surgery would experience “phantom penis” sensations at a lesser rate than people who underwent a penile amputation—not a directly comparable surgery, but the closest analogue for cisgender man—as part of cancer treatment.

Similarly, they expected that transgender men who received a double mastectomy would experience “phantom breast” sensations in lower numbers than cisgender women who had the same procedure.

The underlying logic was almost seductively parsimonious: Because there is often a mismatch between transgender people’s internal body images and their own anatomy, the brain wouldn’t exactly miss certain parts if they were to disappear.

Conversely, we could expect a fair number of transgender people to feel sensations from body parts that aren’t there if their brains simply expected them to be there. Indeed, out of the 30 transgender men they interviewed while working on that first paper, “more than half” said they had experienced “phantom penis” sensations—and “often since early childhood.”

The pair of researchers tested these hypotheses on a very small sample of subjects in a follow-up study.

As expected, the transgender women in the study who had received sex reassignment surgery reported experiencing “phantom penis” sensations at about half the rate reported by cisgender men who had a penile amputation in another, much older study.

There was an even larger gap in self-reported “phantom” sensations between transgender men and cisgender women who had received double mastectomies.

But the sample sizes were far too small and the data points too scant to draw any definitive conclusions—only 29 transgender men and 20 transgender women were surveyed about their “phantom” feelings after surgery—and there haven’t been any larger follow-ups. (As Case reminded The Daily Beast there are some obvious “practical limitations” that make it difficult to do large-scale studies in this area, namely the fact that less than half of one percent of Americans are estimated to be transgender.)

Transgender people themselves have had varying responses to this kind of research. Some, like transgender attorney Noah Lewis, find it refreshing to hear “neurological evidence of the dysphoric feelings that trans people try to describe,” as he wrote in the anthology Gender, Sex, and Politics.

“I take comfort that there are some scientists who can explain being trans in a way that actually matches up with my experience,” he wrote in a section on Ramachandran’s and Case’s work.

Others are generally wary of studies like these being used as biological explanations that would narrowly define transgender identity as a function of hormones or brain size.

As cisgender science writer Deborah Rudacille noted in her book The Riddle of Gender, “I’ve also been cautioned by some trans people about the dangers of biological reductionism, and heard concerns that once again science and medicine are being used to define transgendered [sic] people, to pin a label on them, even if the label may ultimately be a less stigmatizing one.”

That common concern raises critical and potentially sobering questions going forward: Even if we could definitively demonstrate how gender dysphoria works in the brain on a biological level, would opponents of transgender equality give up the fight?

If millions of transgender people affirm that their feelings are real and still fail to persuade some people, can scientists really change transphobic hearts and minds? Is the problem that people don’t know what being transgender feels like—or is it that they don’t care?