A lesbian couple has filed a lawsuit challenging South Carolina's laws banning gay marriage.

Katherine Bradacs and Tracie Goodwin and their attorney, John Nichols, filed their lawsuit in U.S. District Court last week.

The suit challenges the state's marriage law and a 2006 voter-approved constitutional amendment prohibiting the state from recognizing any relationship other than a heterosexual marriage.

“By defining marriage in this way, South Carolina discriminates on the basis of sex,” the lawsuit states. “The Supreme Court has made clear that perpetuation of traditional gender roles is not a legitimate government interest.”

“Neither traditional nor moral disapproval of same-sex relationships or marriage for gay and lesbian couples is a legitimate basis for unequal treatment of same-sex couples under the law.”

Bradacs and Goodwin married last year in the District of Columbia.

The couple want the state to recognize their marriage to qualify for additional federal benefits since Goodwin is classified as a disabled United States Air Force Veteran.

“This suit is really about equal treatment of all South Carolina citizens under the law,” lawyer Nichols told The State. “We should value people who want to live in a committed relationship, regardless of gender.”

The lawsuit names Governor Nikki Haley and state Attorney General Alan Wilson as defendants.