In laying out his reasons for moving on Wednesday to ban transgender people from serving in the U.S. military, President Donald Trump cited the "tremendous medical costs" associated with the policy.

His claim raises several immediate questions, such as exactly how much the Department of Defense spends on providing health care for transgender service members, as well as whether there are enough transgender people in the armed forces to move the needle on the department's annual $6 billion in health care spending on active-duty forces.

....victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail. Thank you

— Donald J. Trump (@realDonaldTrump) July 26, 2017

Likewise, a 2015 study in the New England Journal of Medicine concluded that the health care costs related to transition for transgender service members "is too low to warrant consideration in the current policy debate." Its author estimated the costs at $5.6 million annually, or "little more than a rounding error."