Defense Secretary Ashton Carter announced last July that the Pentagon intended to allow transgender people to serve openly in the military within six months, calling the decades-long ban “outdated” and an impediment to attracting and retaining top talent.

More than eight months later, a new policy has yet to be unveiled. It is imperative that Mr. Carter complete this process in a matter of weeks so transgender troops can start serving openly while he is in office.

A study by the RAND Corporation, undertaken at the request of the Defense Department, recently concluded that repealing the Pentagon’s discriminatory transgender ban would have minimal impact on the force. The study, which has not yet been publicly released, predicted that between 29 and 129 service members would seek transition-related medical care annually. It also found that the change in policy was unlikely to harm unit cohesion and that the cost of providing transition-related care would be negligible.

A task force Mr. Carter convened last year to establish an inclusive policy has drafted regulations addressing how the Defense Department should handle cases of service members who transition after joining the military. But questions remain. Some officials have recommended that transgender troops who transition soon after enlisting should be discharged, but have given no legitimate reasons for this proposal. In any case, such an approach would be discriminatory. There is also some debate over the criteria to use in evaluating whether people who are undergoing transition-related medical treatment are fit for duty.