Navy and Marine Corps maternity leave policies drastically expanded last year will be now slashed by six weeks from 18 to 12 weeks under a new plan announced Thursday by Secretary of Defense Ashton Carter.

The plan, announced as part of other Force of the Future personnel changes, doubles the Army and Air Force's current six-week policies, but dials back a generous leave policy rolled out by Navy Secretary Ray Mabus in August.

"Today I'm setting 12 weeks of fully paid maternity leave as the standard across the forces," Carter said during a press conference at the Pentagon. "I don't take lightly that 12 weeks of maternity leave represents a downshift from what the Navy pursued last summer ... I thought it was important that we have the same standard across the joint force."

Currently pregnant sailors and Marines will still be able to take advantage of the 18-week policy, which went into effect last summer, Carter said. He said officials chose 12 weeks as the standard in attempt to balance personnel benefits with readiness.

"Twelve weeks is extremely generous and puts us in the top tier of American employers," he said. "But then you have to balance that against the readiness costs associated with it."

Carter said he will also seek the authority from Congress to increase paid paternity days for new fathers from 10 to 14.

"For those who want to become dads or are about to, I want them to know that this leave is available to them and I want them to make full use of it," he said.

The secretary is ordering the services to establish "mothers' rooms" at every facility with over 50 women in an effort to help females continue breast feeding after coming back to work. Details were not immediately available on what the rooms would include. He said the order will result in the addition of about 3,600 such rooms across the U.S.

Carter announced a series of other family-friendly initiatives, including increased hours at child care facilities on base to 14 hours a day, and a program that would allow troops to request stabilization at their duty station in exchange for an additional service obligation. No information was immediately available on when those changes would take effect.

Pentagon officials said the services have been given 30 days to develop implemtentation plans for the new policies. It was not immediately clear at what point thereafter the policies would go into effect.

He also announced a pilot program that would allow active-duty troops to freeze their eggs or sperm.

"We can help our men and women preserve their ability to start a family even if they suffer certain combat injuries," he said. "That's why we will cover the cost of freezing sperm or eggs through a pilot program for active duty service members, a benefit that will help provide men and women, especially those deployed in combat, with better peace of mind."

Details on how and where the pilot program would be administered were not immediately available. Carter also said the Department will continue to study offering other reproductive assistance, like IVF, which is currently not covered by Tricare.

-- Amy Bushatz can be reached at amy.bushatz@military.com.