At least eighteen countries allow transgender personnel to serve openly, but the United States is not among them. In this article, we assess whether US military policies that ban transgender service members are based on medically sound rationales. To do so, we analyze Defense Department regulations and consider a wide range of medical data. Our conclusion is that there is no compelling medical reason for the ban on service by transgender personnel, that the ban is an unnecessary barrier to health care access for transgender personnel, and that medical care for transgender individuals should be managed using the same standards that apply to all others. Removal of the military’s ban on transgender service would improve health outcomes, enable commanders to better care for their troops, and reflect the military’s commitment to providing outstanding medical care for all military personnel.