Tennessee - Gay Couples Challenge Marriage Ban - NYTimes.com Four same-sex couples legally married in other states have filed a lawsuit challenging the Tennessee law that prohibits recognition of their marriages. The lawsuit, filed Monday in Federal District Court in Nashville, argues that the law violates the federal Constitution's guarantees of equal protection and due process. Under a United States Supreme Court ruling, gay couples who are legally married in states that allow it are given equal federal footing with other married Americans.