Nixon has directed Missouri’s Department of Revenue to accept joint tax returns from same-sex couples who were legally married in other states.

The Missouri Constitution recognizes marriage only between a man and a woman.

But Nixon noted the federal government is now accepting joint income tax returns from legally married gay couples. He said Missouri law links the state tax code to the federal one.

Attorney general’s spokeswoman Nanci Gonder says Nixon’s policy appears to follow the requirements of Missouri tax law.

But state Rep. Chuck Gatschenberger, a Republican from Lake St. Louis, says he is seeking a formal opinion from Attorney General Chris Koster.