(IDEX Online) - Women alleging sex bias by Sterling Jewelers are calling on the US Supreme Court to allow them to pursue a joint action.A group of 70,000 current and former employees claim Sterling, a subsidiary of Signet Jewelers, paid them less than men and gave them fewer promotions. Sterling strenuously denies the claims.Last November, Sterling persuaded a court that only a few hundred women who had explicitly opted into the legal battle when it began back in 2005 could be part of a class arbitration - effectively denying representation to the vast majority of putative plaintiffs. That overturned a 2015 decision that newcomers could join the dispute. Lawyers for the women this week challenged the U-turn.Sterling requires workers to agree to arbitration as a condition of employment but has repeatedly appealed against the way the process is conducted.Sterling, a specialty jewelry company headquartered in Akron, Ohio, has 1,500 stores and was acquired by Signet in 1987.Pic shows US Supreme Court