Four US servicewomen, including two who won Purple Hearts in Afghanistan, sued the Pentagon over its policy barring women from ground combat.
Backed by rights watchdog the American Civil Liberties Union (ACLU), they slammed the policy as an "injustice to the women ... who continue to put their lives on the line for their country."
In practice women have served in combat roles for years, they said -- but US military policy still bans them, resulting in a "brass ceiling" in which women cannot be promoted because of lack of recognized combat experience.
"Ever since I was a little girl I wanted to be an Air Force pilot, and I have proven my ability every step of the way," said Major Mary Jennings Hegar, a rescue helicopter pilot who flew Medevac missions in Afghanistan.
Her aircraft was shot down in 2009 while rescuing three injured soldiers, and she had to fight, returning fire and sustaining shrapnel wounds. She was awarded the Purple Heart and Distinguished Flying Cross with Valor.
"The ability to serve in combat has very little to do with gender or any other generalization. It has everything to do with heart, character, ability, determination and dedication," said the 36-year-old, quoted by the ACLU.
"This policy is an injustice to the women who have come before us and who continue to put their lives on the line for their country."
Women are still barred from ground combat units, although female troops have found themselves in combat anyway over the past decade in Afghanistan and Iraq, with more than 140 killed on the battlefield.
"Women have more equal opportunity to die for serving their country than to actually be allowed to serve their country," said Army Staff Sergeant Jennifer Hunt, who won a Purple Heart after her vehicle was hit by a roadside bomb.
"The gap between the policy and reality is bad for the armed forces, bad for service members and needs to be changed," added First Lt. Colleen Farrell of the US Marine Corps, speaking to reporters in a conference call.
In February, the Pentagon announced incremental changes that will allow women to serve in more than 14,000 jobs, mostly in the Army and Marine Corps, that had previously been closed to female service members.
But the overall prohibition against women in ground combat remains, denying women the chance to join infantry and armor units as well as special forces.
The ACLU said that 238,000 jobs in the military still remain closed to women.
Tuesday's lawsuit was filed in federal court in San Francisco, by the four servicewomen and the Service Women's Action Network, represented by the ACLU's Northern Californian office and the law firm Munger, Tolles and Olson.
It names Defense Secretary Leon Panetta as the defendant.
Pentagon spokesman George Little said Panetta was committed to expanding women's roles in the US military.
"On his watch, some 14,500 positions have been made been available to women, and he has directed the services to explore the possibility of opening additional roles for women in the military," he said.
"So I think his record is very strong on this issue. The recent openings that I just referred to are really the beginning and not the end of the process, and we expect that process to continue"
Along with Hegar, Farrell and Hunt, the fourth plaintiff in the lawsuit is Captain Zoe Bedell, whose Marine Corps Female Engagement Teams (FET) lived with infantrymen and frequently encountered combat situations.
"These women served their country bravely and honorably and have demonstrated their ability to distinguish themselves under fire just as much as their male comrades," said ACLU lawyer Ariela Migdal.
"This antiquated policy doesn't reflect the nature of modern warfare or the actual contributions of women in uniform," she added.