A decades-old measure banning transgender Americans from joining the armed forces might soon be lifted.

A probe conducted by an ex-United States surgeon general found "no compelling medical reason" for trans citizens to be barred from serving, the Associated Press reported.

President Barack Obama now has the option of lifting the ban, with or without Congress' rubber stamp of approval.

The report released this week stated that the rules established by the Department of Defense are now outdated - the regulations give service members a choice to either leave the force or skip gender reassignment surgery.

"We determined not only that there is no compelling medical reason for the ban, but also that the ban itself is an expensive, damaging and unfair barrier to health care access for the approximately 15,450 transgender personnel who serve currently in the active, Guard and reserve components," ex-surgeon general Dr. Joycelyn Elders wrote in her findings.

Elders, who worked for Bill Clinton during his first term as president, led the study with co-author Rear Adm. Alan Steniman, an ex-chief health and safety director for the United States Coast Guard, AP reported.

According to a panel of San Francisco State University officials, the ban has been in place for a few decades, and reportedly stemmed from a past psychiatric conclusion that gender identity issues were rooted in mental illness. The restrictions also stated that sex reassignment surgery and hormone regimens were too costly and troublesome to carry out.  

But the commission maintained that allowing gender transitions for service members "would place almost no burden on the military."

"I hope their takeaway will be we should evaluate every one of our people on the basis of their ability and what they can do, and if they have a condition we can treat we would treat it like we would treat anyone else," Elders told the Associated Press in an interview ahead of the probe's release.

Transgender citizens are currently allowed to serve in more than 12 countries - Canada, England, Australia and Israel among them.