The United States Defence Department is to allow women to serve aboard submarines.
Women have worked alongside men on Navy surface ships and planes since 1993, but it was thought the very cramped conditions in submarines precluded both sexes working together: 15% of US Navy personnel are female.
It's expected it will take a year before the first women can be trained for submarine duties and before the vessels can be modified to provide separate quarters for men and woman.
The BBC reports women are still barred from traditional frontline roles in the armed forces. General George Casey told Congress on Tuesday that he supports a reconsideration of the role of women in combat.