JEFFERSON CITY - Same-sex couples cannot file joint tax returns in Missouri, according to the Department of Revenue.
The Internal Revenue Service only allows same-sex couples to file jointly if the state where they live recognizes gay marriages.
"At this point we don't have gay marriages in Missouri, so you would not be able to file jointly for federal purposes," said Department of Revenue spokesperson Jessica Robinson. "You file your state taxes the same way you file your federal taxes."
Robinson said same-sex couples with some Missouri income may be able to file jointly if they live in a state that recognizes gay marriages.
"If the federal government accepts that return, then we would accept it as well," Robinson said.
Gay marriage has become the focal point of debate over the past several weeks following the Massachusetts high court's ruling that same-sex couples have the right to marry.
The opinion was issued after the Massachusetts Senate asked the court if civil unions, which allow the benefits without the title of marriage, would be acceptable under their interpretation of the state's Constitution.
Under the Full Faith and Credit Clause of the U.S. Constitution, states must observe the judicial decisions of other states.
The controversy over gay marriage was heightened after San Francisco Mayor Gavin Newsom began granting marriages to same-sex couples. California law only recognizes marriage between a man and a woman, which Newsom holds is discriminatory under the state Constitution.
Marriage licenses have also been granted to same-sex couples in New Mexico.
Missouri law prohibits gay marriage, even if the marriage was valid where it took place.
A proposed amendment to the Missouri Constitution would also define marriage as a union between a man and a woman.
Proponents believe the amendment is necessary to help stalwart the state's defenses against "judicial activism."
"Ask Massachusetts. Ask California. When the judiciary legislates from the bench, we have to clarify for the judges in no uncertain terms that this is the Missouri voters' wishes," Rep. Kevin Engler, R-Farmington, said.
While Full Faith and Credit would require Missouri to recognize same-sex marriages from other states, Engler said he thought the decision would ultimately be made in court.
"We would hope that it would be clear that we have no intent on recognizing marriages from other states after we pass (the amendment) that are of the same sex," Engler said.
Opponents said the proposed amendment would be discriminatory and unnecessary.
"This would be the first time ever that our state Constitution would be used to discriminate against a group of Missourians," said Jeff Wunrow, Executive Director of PROMO, a gay and lesbian rights group.
Separate versions of the amendment are expected to be debated in the House and the Senate early this week.