Four same-sex couples in Indiana, including two who legally married in other states, filed a federal lawsuit Friday seeking to invalidate the Hoosier State’s definition of marriage as being between a man and a woman.

The plaintiffs want either to be allowed to wed or to have their marriages recognized by Indiana, granting them in either case the same legal protections as opposite-sex couples.

At the center of their argument is the U.S. Supreme Court’s decision last year to strike down the federal Defense of Marriage Act on the grounds that it discriminated against same-sex couples. Since then, several federal judges have made rulings favorable to gays and lesbians.

The plaintiffs in Indiana said Friday that the ban had caused them troubles on tax returns, healthcare and adoptions, among other things.

"When we file our taxes, we have to put it together for federal purposes, and we take it apart again for Indiana," Jo Ann Dale said at a news conference alongside her partner, Carol Uebelhoer. "It feels so schizophrenic to not be recognized for who we are."

Indiana’s Defense of Marriage Act defines marriage as being between one man and one woman. Marriages from out of the state that don’t meet that definition aren’t recognized; such is the case for Dale and Uebelhoer, who wed in 2008 in Massachusetts.

Indiana Attorney General Greg Zoeller, a Republican, vowed to defend the law.

"As state government’s lawyer, I must defend the state’s authority to define marriage at the state level within Indiana’s borders," he said in a statement Friday. "People of goodwill have sincere differences of opinion on the marriage definition, but I hope Hoosiers can remain civil to each other as this legal question is litigated in the federal court."

Supporters of traditional marriage signaled their dismay at the lawsuit.

"For years we have warned legislators and policy leaders that homosexual activists were seeking to force a new definition of marriage upon every church, school and business in Indiana," said Micah Clark, executive director of the American Family Assn. of Indiana.

He said the "issue now rests in the hands of unelected judges . . . rather than letting the people of Indiana decide the future of marriage."

Among the others suing Indiana are Melissa Love and Erin Brock, who want to marry, and Michael Drury and Lane Stumler, who also want to marry. The fourth Indiana couple, Jennifer Redmond and Jana Kohors, married in New York in 2013.

The couples are represented by attorney Dan Canon of Kentucky. Last month, Canon won a similar case in federal court in his home state.

U.S. District Judge John G. Heyburn II in Louisville ruled that Kentucky’s gay marriage ban violated the U.S. Constitution’s equal-protection clause because it treated same-sex couples differently. If the state of Kentucky isn’t granted an appeal, gay marriages become legal there on March 20.