4th day of testimony challenging gay-marriage ban

      A Harvard University professor has testified for two women challenging Michigan's gay-marriage ban.

      Nancy Cott says Michigan is falling behind other states by failing to recognize or allow same-sex marriage. She's a historian who has studied marriage in America.

      Michigan voters banned gay marriage in 2004, but two Detroit-area nurses are asking a judge to throw it out, saying it violates the U.S. Constitution.

      The state attorney general's office will start presenting witnesses Monday. The state has defended the constitutional amendment as a way to promote family stability through households led by a man and a woman.

      Gay-marriage bans have been struck down in other states in recent weeks.