New Defense Secretary Ash Carter signaled support for allowing transgender individuals to serve in the military, the latest sign that the controversial policy may change before the end of the Obama administration.

"I don't think anything but their suitability for service should preclude them," Carter said while speaking to troops on a visit to Kandahar, Afghanistan, on Sunday.

A Navy officer raised the issue during a town hall-style meeting that Carter held with service members during his visit. The officer asked: "What are your thoughts on transgender service members serving in an austere environment like this here in Kandahar?"

"It's not something I've studied a lot since I became secretary of defense," Carter said, "but I come at this kind of question from a fundamental starting point, which is that we want to make our conditions and experience of service as attractive as possible to our best people in our country.

"And I'm very open-minded about ... what their personal lives and proclivities are, provided they can do what we need them to do for us. That's the important criteria. Are they going to be excellent service members?" Carter said.

His comments came shortly after the Pentagon launched a review that could result in lifting the ban on transgender individuals from joining the military.

Lt. Cmdr. Nathan Christensen, a Pentagon spokesman, said there is "no specific review of the department's transgender policy ongoing" but acknowledged that military health officials began in early February an official reassessment of the current medical accessions policy.

That policy prohibits military service by people who have a "current or history of psychosexual conditions, including but not limited to transsexualism, exhibitionism, transvestism, voyeurism and other paraphilias."

"We routinely review our policies to make sure they are accurate, up-to-date and reflect any necessary changes since the department's last policy review," Christensen said.

The last review of this policy was conducted in 2011. The current periodic review is expected to take 12 to 18 months, Christensen said, emphasizing that it "is not a specific review of the department's transgender policy."

This particular medical accessions policy is potentially the last piece of Pentagon policy that explicitly prohibits transgendered individuals from serving. Last year, officials quietly rewrote a policy that removed specific reference to transgenderism in the Disability Evaluation System.

Advocates for transgender individuals viewed that as a new loophole that could allow the services to let transgender troops to continue to serve instead of requiring administrative separation.

Advocates for gay, lesbian, bisexual and transgender service members hope that the Pentagon will change the policies soon, particularly before President Obama leaves office in January 2017. Obama was a strong advocate for the 2011 repeal of the "don't ask, don't tell" law that lifted restrictions on gays and lesbians serving openly in the military.

Advocates welcomed Carter's comments and said the new secretary should follow them up with a change to the policy.

"Secretary Carter is right in that their ability to serve is the only thing that should matter," said Ashley Broadway-Mack, the president of the American Military Partners Association, a group that has lobbied for equal treatment for same-sex military spouses.

The AMPA estimates that more than 15,000 transgender individuals serve in the military today.

"Thousands of transgender service members ARE currently doing the job, and doing it well, but are forced to do so in silence — forced to lie about something as fundamental as who they are in order to continue to serve," Broadway-Mack said.

"While we applaud Secretary Carter for being 'open-minded' on this issue, we urge him to take action that will lead to ending this ban that continues to harm our transgender service members and their families."

The military's civilian leadership has been suggesting for months that the controversial policy may change. In December, Air Force Secretary Deborah Lee James said in an interview with USA Today that the policy "is likely to come under review in the next year or so."

"Times change," James said. "From my point of view, anyone who is capable of accomplishing the job should be able to serve."

And former Defense Secretary Chuck Hagel said in an interview with Military Times in January that he does not see any reason why the military services could not adjust to accepting transgender individuals.

"This institution has been on the cutting edge of social change in this country since World War II," Hagel said in the Jan. 21 interview. "For all the reasons I think anybody whoever serves in the military understands, we rely on each other to do the job. If there is a weak link in the chain, the chain is weak.

"I have great confidence that we are going to continue in this institution to be able to handle these kind of things as they progress along just as we have don't ask, don't tell, gay marriage."

Regarding the issue of transgender service members specifically, Hagel said: "I would not say there is nothing unique about it. But what I am saying is that this institution has been able to handle and transition into these different situations as they are required to do to respect the rights of individuals and the desires of individuals to serve and also the standards and the rights of the institution.

"We have been able to deal with that over the years. The transgender issue is a fairly new issue, just as each of these issues were. The integration of our services after World War II. Don't ask, don't tell. Gay marriage. ... I have confidence in the process and the system that the transgender issue will be dealt with in a fair way."