The research shows that gender transition improves well-being, and that it can redress the specific health conditions that the military claims are its primary concern, particularly suicidality. A 1999 United States study found a “marked decrease of suicide attempts” and substance use in its postoperative population. In a 2014 British study, gender transition “was shown to drastically reduce instances of suicidal ideation and attempts.” The study reported that “67 percent of respondents thought about suicide more before they transitioned and only 3 percent thought about suicide more post-transition.”

Research suggests that gender transition may resolve symptoms completely. A 2016 literature review by scholars in Sweden concluded that, most likely because of improved care over time, transgender “rates of psychiatric disorders and suicide became more similar to controls,” and that for those transitioning after 1989, “there was no difference in the number of suicide attempts compared to controls.” The corollary is also true: Another study found that withholding hormone treatment from transgender people increased the risk of depression and suicide.

While transgender people can still face disproportionate stresses after transition, research suggests that stigma and discrimination are primary causes of such “minority stress.” That’s all the more reason we should provide treatment and social support rather than exclusion and barriers to care.

Suicide and mental health challenges do not, of course, define transgender people, many of whom are just as healthy as their peers. There are other populations that are plagued by suicide, including the military community itself. Children of military members are at much higher risk for suicidal ideation than both the general and the transgender population. Yet children of service members are not barred from enlisting, despite these higher risks. This suggests a double standard in which transgender people are singled out for unequal treatment not because they present an unacceptable risk but simply because of bias.

The studies we reviewed, like all research, have methodological limitations. It’s virtually impossible, as well as unethical, to conduct randomized, controlled trials on transition care because of the small size of the transgender population and because it would require withholding treatment from those who need it.

Yet even with these limitations, the quality and quantity of research on gender transition are robust, showing unmistakably that it’s highly effective. The only way to call this kind of a consensus “uncertainty” is to ignore all the research that doesn’t support a specific agenda, which appears to be just what the Pentagon did.