The Few, the Proud, the Women Score one for fairness: the Marine Corps is about to let women take the Infantry Officer Course, a notoriously punishing test that prepares lieutenants to lead infantry platoons into combat. The course, as C. J. Chivers of The Times recently explained, requires students to endure extreme heat, stress, exhaustion and disorientation while staying mentally sharp - written exams are mixed among the physical ordeals - for 86 days. About 300 men pass each year. Starting in September, women will be allowed to take the course, but because it is an experiment they will not become infantry officers even if they pass. The Marines hope at least 92 women will sign up to form a sufficient statistical sample to help make recommendations about expanding women's combat roles. Though women have been on the battlefield in every one of America's wars, and more than 250,000 have served in Iraq and Afghanistan, they are officially barred from direct ground fighting. We hope this test is a step toward ending an injustice that ignores women's long history of achievement under fire. A sex-segregated military not only unfairly limits women's career advancement, but it also limits itself. A fighting force that draws leaders from a larger pool will have better leaders. A global force with women on the front lines will be more effective and adaptable in combat. That the Marines are even allowing women to take this course is remarkable. "The Marine Corps to me typifies everything that is hypermasculine and misogynistic about the military," said Anu Bhagwati, a former Marine captain and executive director of Service Women's Action Network, which advocates for equal treatment for military women and veterans. When she heard about the experiment, she said, "My jaw just dropped. I never thought I'd see it while I could still walk. The strength and valor of military women are not in dispute. This experiment can prove that again.