NEW YORK ( TheStreet) -- Wal-Mart ( WMT - Get Report)is entwined it what could be the largest sexual discrimination class-action lawsuit in U.S. history. A U.S. appeals court ruled on Monday that a lawsuit brought by female Wal-Mart employees can go to trial, which could result in billions of dollars in losses for the discount giant. The workers are alleging that Wal-Mart pays women less than men for the same jobs and that female employees receive fewer promotions. The suit was first filed in a federal court in San Francisco in 2001. Since then Wal-Mart has lost two rulings in trial court and another in the appeals court in 2007. -- Reported by Jeanine Poggi in New York. Follow TheStreet.com on Twitter and become a fan on Facebook.