As arguments rage over the sources of transgender identity, science weighs in

A cloud of controversy hovers over scientific research on transgender identity, but not necessarily because of the research itself. Ideologues threatened and unsettled by gender fluidity question research they don’t like, while activists on the opposite side do the same. Bias is antithetical to properly assessing scientific findings, so slanted discussions often don’t get anywhere.

Today, I’ll turn to the scientific literature to tackle three controversial questions about transgender identity.

1. Can gender dysphoria, in which a person’s gender identity does not match their gender assigned at birth, be affected by social factors?

Maybe. A recent study published to PLoS ONE drew condemnation from some and praise from others. Lisa Littman, an Assistant Professor of the Practice of Behavioral and Social Sciences at Brown University, surveyed 256 parents of teens experiencing rapid-onset gender dysphoria. The collected surveys revealed that gender dysphoria was linked to a prior increase in social media/Internet use and “seemed to occur in the context of belonging to a peer group where one, multiple, or even all of the friends have become gender dysphoric and transgender-identified during the same timeframe.” This suggests that social interactions may affect feelings of gender dysphoria.


Upon the study’s release some called for it to be censored and retracted, while others hailed it as a “very important, peer reviewed study” of an “awful epidemic.”

Both reactions are overblown. The study is very preliminary and carries the same flaws inherent to social science in general – a biased sample group, lack of controls, results open to interpretation – which Littman duly noted. If you retract this study, you might as well retract half of all social science research. At the same time, it is outlandish to label gender dysphoria an “awful epidemic” – self-reported transgender identity in children, adolescents and adults ranges from 0.5 to 1.3%. Moreover, it is a gross overextension of the research to for anyone to conclude that gender dysphoria is purely the result of social factors.

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2. Is being transgender a mental illness?

No. While some outspoken commentators espouse this notion, there’s no good evidence to back it up. According to the American Psychological Association, “A psychological state is considered a mental disorder only if it causes significant distress or disability. Many transgender people do not experience their gender as distressing or disabling, which implies that identifying as transgender does not constitute a mental disorder.” Moreover, the World Health Organization no longer classifies being transgender as a mental illness.


While transgender identity is not a mental illness, transgender people and those experiencing gender dysphoria are more susceptible to depression, anxiety, and ADHD. However, a systematic review found that psychiatric symptoms vastly improve following gender-confirming medical interventions. It seems that when transgender people are permitted to assume their gender identities, they become happier and healthier individuals.

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3. Are there brain differences associated with being transgender?

Yes. Male and female brains are structually different, and fascinatingly, studies show that the brain structure and brain activity of transgender people more closely resemble those of their gender identity versus their birth gender. This suggests that sexual differentiation of the brain during the development is not necessarily linked to sexual differentiation of the genitals.

“During the intrauterine period a testosterone surge masculinizes the fetal brain, whereas the absence of such a surge results in a feminine brain. As sexual differentiation of the brain takes place at a much later stage in development than sexual differentiation of the genitals, these two processes can be influenced independently of each other,” researchers Ai-Min Bao and Dick F. Swaabb wrote.


Though we don’t know exactly what biological mechanisms influence transgender identity, we can conclude with a fair amount of certainty that being transgender is heavily influenced by biology.

Steven “Ross” Pomeroy is Chief Editor of RealClearScience. A zoologist and conservation biologist by training, Ross has nurtured a passion for journalism and writing his entire life. Ross weaves his insatiable curiosity and passion for science into regular posts and articles on RealClearScience’s Newton Blog. Additionally, his work has appeared in Science Now and Scientific American. Follow him on Twitter @SteRoPo  

A version of this article was originally published on Real Clear Science’s website as “Navigating the Controversial Science on Transgender Identity and has been republished here with permission.

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