The final witness for two women challenging Michigan's gay-marriage ban is a Harvard University professor who has written a history of marriage in the U.S.
Nancy Cott is testified today in Detroit federal court on the fourth day of a rare trial. 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.