President Trump announced that transgender troops won't be allowed to serve in the military on July 26, reversing the Pentagon's 2016 decision to lift the ban. (Jenny Starrs/The Washington Post)

President Trump said on Twitter Wednesday that he “will not accept or allow” transgender people from serving in the military in any capacity, reversing a 2015 policy by the Obama administration to allow openly transgender troops in the force.

The sudden announcement stunned lawmakers. Senate Armed Services Committee Chairman John McCain (R-Ariz.) said, “There is no reason to force service members who are able to fight, train and deploy to leave the military — regardless of their gender identity,” while Trump ally Sen. Orrin G. Hatch (R-Utah) voiced a need for more clarity on the proposed changes.

Incoming White House press secretary Sarah Huckabee Sanders defended Trump’s decision to overturn a “very expensive and disruptive policy” during a news briefing Wednesday, saying his national security team “came to the conclusion that it erodes military readiness and unit cohesion.”

White House press secretary Sarah Huckabee Sanders on July 26 said allowing transgender people in the military is a "very expensive and disruptive policy." (Reuters)

Proponents say allowing transgender troops in the armed forces opens up a previously closed recruiting pool of Americans. Transgender people are twice as likely to serve than non-transgender peers, according to a study.

A 2016 study by RAND Corp, commissioned by the Pentagon and the most prominent analysis of the issue, points to a different conclusion from Trump. The group assessed the potential costs of medical care transgender troops might need, along with an analysis on how it could affect readiness or erode unit cohesion.

In summary, the study found:

  • Foreign military commanders who had similar policies were encouraged by overall improved cohesion.
  • Medical costs on the whole were “negligible” among total military medical spending.
  • Concerns a social policy seen by potential recruits as regressive might be turned away from service.

RAND estimates there are between 1,320 and 6,630 transgender people serving on active duty, and as many as 4,160 in the reserves.

The Washington Post spoke with Radha Iyengar, a senior economist at RAND who was one of the seven authors of the study. She has also served on staff positions at the National Security Council and the Defense Department. The interview has been edited for length and clarity.

What the study looked to find

The Washington Post: Can you give a lay of the land of the concerns some in the military have, and some of the benefits you found of transgender troops in the force?

Iyengar: The Department of Defense, in 2015, and possibly even before that, reviewed its policy on allowing transgender personnel to serve openly and receive gender transition-related treatments during military service.

So just to be clear, there are three parts to that.

One is: Can people who are openly transgender join the military?

The second is: When they’re serving in the military, can they serve openly as their target gender?

And third is: What types of gender transition-related treatments can they receive during military service, and how can those costs be covered?

What the Department of Defense was trying to understand is, what are the total costs of that?

And by total costs, I mean both the monetary costs from covering medical treatments and medical care, and the readiness costs of allowing transgender members to serve openly.

Are they not going to be able to deploy, are there more likely to be effects on unit cohesion, and how does that compare to the costs of not allowing them to serve? So that’s where our study came in.

Key takeaways

The Post: Was the RAND study used to drive policy implementation? What were some of your key takeaways in the report?

Iyengar: I think our study was cited at the time when [Defense] Secretary [Ash] Carter made his decision, and I think it provides some important context for what the likely costs are to be. But also some suggestions on how best to transition toward a system where you allow transgender service members to serve openly.

There are a lot of concerns about how many openly transgender personnel there are, and what are their costs likely to be.

Let’s talk about the active component, which is easiest for numbers. If you take 1.3 million active members, you’re looking between 1,300-6,600 transgender serving personnel.

Of those, only a fraction are likely to seek transition-related treatment like mental health care, hormone replacement therapy and medical treatments including surgery.

You have only a few thousand out of 1.3 million. Of those, only a fraction are seeking extreme or invasive treatments. I’m talking between 10-130 service members seeking medical treatments that might affect their ability to deploy.

Those medical costs are about one-tenth of 1 percent of medical costs at DoD.

What the numbers tell us

The Post: The study estimates 30-140 new hormone treatments are initiated in a year, and 25-130 gender transition surgeries a year. On the scale of spending, what do those numbers come out to?

Iyengar: That comes out to about $2.4 [million] to $8.4 million total. It’s a negligible cost in the military health-care system.

And you can say the same thing about the readiness effects. We’re looking at 10-130 active component members who could have reduced deployability. In 2015, about 50,000 soldiers alone were not deployable due to medical reasons in the active component. So the scale of the effects here are relatively small.

Eighteen countries allow transgender personnel to serve openly, including Australia, Canada, Israel and the United Kingdom. Those are countries that have some operational requirements and in some cases operational tempos that are not dissimilar to the U.S.

And we did not find any evidence of effect on unit cohesion or readiness impacts from allowing transgender personnel to serve openly in those countries.

What the White House got wrong, according to the expert

The Post: The discussion coming from the White House today is eroding unit cohesion and tremendous medical costs are reasons to implement this ban. Are you saying that does not square with what you found in the report?

Iyengar: That is correct. I think the evidence is not consistent with the idea of high medical or readiness costs, including unit cohesion, to allowing transgender personnel to serve openly.

The Post: Does longer historical data give you insight of how the policy plays out socially, and in the realm of costs?

Iyengar: I don’t think anyone has had it for that long for us to be able to say.

In the core group of Canada, Israel, Australia and the U.K. that we focused on, a lot of what they saw was the need to have a clear process. So explicit policies, training and education for the force, and clear harassment policy and enforcement of that policy to really have this become effectively integrated.

We’ve had commanders report that having a more improved attitude toward inclusiveness and diversity was beneficial to their unit overall. And that really speaks to the benefits, but there was really no effect, in any of the cases, of operational effectiveness. They saw these positives but we really didn’t see any of the negatives.

What will this new policy mean?

The Post: Is a transgender policy a bellwether of how accepting a force has been, or progressive in terms of their recruiting?

Iyengar: This is speculating outside the bounds of the study. But I think it indicates the force’s priority of having capable individuals being able to serve as long as they are able to meet the physical requirements, rather than having other social tests.

What will this mean for recruitment?

The Post: Brad Carson [former congressman who worked on transgender policy deliberations under the Obama administration] said when he talked to the Joint Chiefs before and asked if it was their preference to reverse the policy, they said it was not. Have you found satisfaction with commanders?

Iyengar: I haven’t heard from commanders in recent months. I will say in the study, we looked at costs from having transgender personnel who are serving who are not able to reveal their gender, and individuals who would be desirable recruits who would be excluded for reasons related only to gender identity.

There are real costs to the manpower losses of having separation and continued ban on open service, and there are concerns that affect productivity and result in unnecessary separation at a time readiness of service members is really expensive. So we really want to retain those people.

A secondary concern is really thinking of how to recruit the best sorts of people and get them into the military. There is a concern that when you have these types of discriminatory policies, that can create different perceptions among recruiting pools the military might like to target. Cyber-based skills, computer skills, that sort of thing.

The Post: Is it possible this decision could have a chilling effect among millennial recruits with those skills at a time when the Army is looking to increase its size by 6,000? Does this further complicate the goal of meeting mission for recruits?

Iyengar: We don’t have estimates to speak to that. I would point out that we do identify those potential costs of not allowing open service.

Read more:

The Pentagon’s ban on transgender service just fell, and the details are complicated

Trump administration rolls back protections for transgender students