A federal lawsuit filed Friday in North Dakota leaves no state with a gay marriage ban without an active case challenging it.

Plaintiffs in the case are seven gay and lesbian couples who are being presented by Minneapolis attorney Josh Newville, who is also representing six couples in a lawsuit challenging South Dakota's marriage ban.

The suit, filed in U.S. District Court in Fargo, claims the state's restrictive marriage ban violates the 14th Amendment to the U.S. Constitution.

“The marriage bans inflict serious and irreparable harms upon same-sex couples and their children that cannot be explained by reference to any legitimate government interest,” the complaint states.

Seventy-three percent of voters in 2004 approved an amendment to the state's constitution defining marriage as “between a man and a woman.” The prohibition also appears in state statutes.

Carl Tobias, a constitutional law professor at the University of Richmond School of Law, told the AP that since North Dakota was the last state to jump into the fray, its case is not likely to reach the U.S. Supreme Court, where the issue is expected to be decided.

“It's symbolic, but sometimes symbolism is important, right? I think it has real, practical, actual effects on people nationwide and in North Dakota,” he said.

Evan Wolfson, president of Freedom to Marry, said that with all 31 state marriage bans facing at least one active marriage lawsuit, now was the time for the Supreme Court to take up the issue.

“With today's addition of North Dakota, courts in every state are considering a freedom to marry case – 70-plus cases in total. With 50% of Americans believing the freedom to marry is a constitutional right, and a strong majority supporting marriage for gay couples, it's time the Supreme Court bring resolution nationwide. The time is now to get on the right side of history,” Wolfson said in a statement.