A Pittsburgh law firm is poised to square off in a federal appeals court against one of its own partners in a potentially groundbreaking sex discrimination suit that could open the door to women lawyers suing for equal pay — even after they have been named partners.

Attorney Alyson J. Kirleis’ suit against Dickie McCamey & Chilcote already set a legal precedent when the 3rd U.S. Circuit Court of Appeals held that she could not be forced to arbitrate her claims, rejecting the firm’s argument that its bylaws mandate arbitration.