SEATTLE, Wash. (Metro) -- Seattle is joining a lawsuit to overturn the federal Defense of Marriage Act. Mayor Mike McGinn and City Attorney Pete Holmes says the act passed by Congress in 1996 is hurting city employees. The act defines marriage as a union between a man and a woman. Channel 13 quoted one city employee who says he and his same-sex partner unfairly pay far more in federal taxes because of the act. Copyright © 2012 Metro Networks Inc.