A gay couple from Cheyenne in the US state of Wyoming have filed a federal lawsuit claiming the state’s refusal to allow them to marry is unconstitutional.

The lawsuit, which is being brought by David Shupe-Roderick, 25, and Ryan Dupree, 21, is the first known legal challenge to be brought against the state of Wyoming’s insistence that marriage is a contract taking place solely “between a male and a female person”.

The couple, who failed to obtain a marriage license from the Laramie County Clerk’s Office despite three attempts to do so, will be representing themselves in the lawsuit.

As reported by Wyoming’s Star Tribune, the two men are requesting that District Judge Alan B. Johnson prevent the state from enforcing any laws which block gay men and lesbians from entering into civil marriage with their partners.

Mr Shupe-Roderick said: “I think it’s time Wyoming lives up to its title. You know they call themselves the equality state? Well, they’re not so equal.”

He added that the reason they sought to represent themselves was simply because they couldn’t afford a lawyer. Mr Shupe-Roderick, who has a degree in criminal justice, said: “If I have to do this on my own, I will, because it’s a cause I believe in.”

However, Wyoming state law does recognise same-sex marriages performed legally in other states. This legal loophole was exploited by groups calling for a “Defence of Marriage” resolution last year, which would have amended the state’s constitution to define recognised marriages within its borders as being solely between a man and a woman. The Defence was not successful.