US Navy Secretary Ray Mabus wisdom: "We could not run the navy without women today."

The first women submariners are likely to be aboard ballistic and guided-missile submarines as they have more living space and will not require alterations.

Chief of Naval Operations, Adm Gary Roughead, said: "It would be foolish to not take the great talent, the great confidence and intellect of the young women who serve in our navy today and bring that into our submarine force."

On the gender front, however, submariners have been hold-outs. Female sailors on submarines, some have argued, will compromise missions when they become pregnant, will complicate the already fragile social ecosystem of the submarine, and will add stress to wives ashore.

About 15% of US navy personnel are women.