Washington (CNN) Speaking at the Virginia Military Institute on Tuesday, Defense Secretary James Mattis said "the jury is out" on the success of having women serve in infantry roles, noting that the sample size remained too small to make clear determinations.

"This is a policy I inherited, and so far the cadre is so small we have no data on it. We're hoping to get data soon," Mattis said.

In January 2017 , the first three women infantry Marines were added to an infantry battalion at Camp Lejeune in North Carolina, but women didn't always have the opportunity to serve in the same combat positions as men.

Former Defense Secretary Ash Carter announced in 2015 that starting in January of the following year, the military would require all combat roles be open to both men and women. However, uncertainty over whether Mattis would continue this policy has remained despite his statement during his confirmation hearing that he had no plans to reverse the policy.

"This is an area we're going to have to resolve as a nation," Mattis said Tuesday. "And the military has got to have officers who look at this with a great deal of objectivity, and at the same time, remember our natural inclination to have this open to all. But we cannot do something that militarily doesn't make sense."

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