The national trend of litigation to challenge bans on same-sex marriage is continuing in the Lone Star State. Two couples in Texas have filed a federal lawsuit to challenge that state's ban on same-sex marriage, arguing the ban violates the federal constitution and the Texas state constitution, the San Antonio Express-News reports. “There is no rational basis, much less a compelling government purpose, for Texas to deny plaintiffs the same right to marry enjoyed by the majority of society,” the plaintiffs' complaint said, according to the newspaper.