WASHINGTON — Defense Secretary Ashton Carter’s landmark decision Thursday to open all jobs to women in the military was greeted by many as a sign of changing times and a move toward true gender equality. But it also raises a related question: Will women be required for the first time ever to register for military drafts, and is it constitutional if they are not?

The Selective Service System has existed for decades, and is used to provide the U.S. military with enough manpower when it is short-handed in a time of war. A variation of it was adopted in 1917, ahead of World War I, and it has been updated over the years.

Selective Service laws, however, have never required women to subject themselves to the draft and face the prospect of being forced into military service. The current version of the Military Selective Service Act requires that virtually all men in the United States between the ages of 18 and 26 register, most within 30 days of turning 18. That includes non-U.S. citizens living in the United States, such as refugees. But women are entirely exempt.

The Defense Department has prepared an analysis of how the Pentagon change could affect the Selective Service Act, said White House spokesman Josh Earnest.

“We’re going to work with Congress to look at that analysis, to review it, to get others’ opinions and determine if additional reforms or changes are necessary in light of this decision,” Earnest said.

Earnest said President Barack Obama has not expressed his views to the Pentagon.

Carter said Thursday that he did not know how the issue would be resolved, but acknowledged that it is a “matter of legal dispute right now.” He added that “unfortunately,” it is subject to ongoing litigation. At least two lawsuits have been filed against the Selective Service System since the combat exclusion policy was appealed in 2013.

In one, a New Jersey girl sued saying the system was discriminatory because it did not consider women for the draft. In another, the nonprofit National Coalition for Men did the same, citing the Rostker vs. Goldberg decision. The latter case is expected to be reviewed by the 9th U.S. Circuit Court of Appeals in Pasadena, Calif., on Tuesday.

The Washington Post and the Associated Press contributed to this report.

