The lawsuit accuses the government of violating the constitutional rights of servicewomen by excluding them from certain ground combat units and other positions solely because of their gender.

It seeks to require the military to make all assignments and training decisions without regard to gender.

The defendants named in the lawsuit, which was filed on Wednesday in Federal District Court in Washington, are Secretary of Defense Leon E. Panetta; the secretary of the Army, John M. McHugh; the Army’s deputy chief of staff, Lt. Gen. Thomas P. Bostick; and an assistant secretary of the Army, Thomas R. Lamont.

It is the first lawsuit to challenge the combat ban, said Anne M. Coughlin, a University of Virginia Law School professor whose effort to look into the policies led to the lawsuit.

Command Sgt. Maj. Jane P. Baldwin and Col. Ellen L. Haring argue that the policies unconstitutionally bar women from certain positions available to men and restrict earnings, opportunities for advancement and future retirement benefits.

The lawsuit notes that women are already serving in combat in Iraq and Afghanistan, and says that instead of assigning them to combat units, the military was circumventing the exclusion by “attaching” them to such units.

Colonel Haring, of Bristow, Va., has been a platoon leader, a commander, an executive officer and a bridge commander over a 28-year Army career. The lawsuit says her options “were limited to support positions with no possibility to compete within the combat arms.”

The ban has also caused Colonel Haring and Sergeant Major Baldwin, a resident of Tallahassee, Fla., who has served for more than 20 years, to “suffer invidious discriminatory treatment in a work environment that institutionalizes the unequal treatment of women solely because of their sex and notwithstanding their individual abilities,” the lawsuit said.

A Defense Department spokesman, Todd Breasseale, declined to comment specifically about the lawsuit on Friday. But he said Mr. Panetta remained “strongly committed to examining the expansion of roles of women in the United States military, as evidenced by the recent step of opening up thousands more assignments to women.”

The change will open up about 14,000 jobs for women, but more than 250,000 remain closed.

The new openings in combat battalions are personnel, intelligence, logistics, signal corps, medical and chaplaincy jobs. The Army is also opening jobs, like tank mechanic and artillery and rocket launcher crew member, that were once entirely closed to women.

Click here to read more from The New York Times.