The Iowa Supreme Court has voted to allow gay marriage in the state.

In a summary of the unanimous decision, the judges said: “The Iowa statute limiting civil marriage to a union between a man and a woman violates the equal protection clause of the Iowa Constitution.”

The lawsuit, Varnum vs. Brien, involved six same-sex Iowa couples who sued Polk County Recorder Timothy Brien in 2005 after they were denied marriage licences by his office.

They challenged state laws which say marriage can only be between a man and a woman.

In December 2005, charity Lambda Legal filed a lawsuit with the Polk County Court on behalf of the six same-sex couples, arguing that denying marriage to same-sex couples violates the liberty and equality guarantees in the Iowa State Constitution.

In August of 2007 the district court ruled that denying marriage to same-sex couples is unconstitutional.

In March 2008, 15 friend-of-the-court briefs were filed supporting same-sex couples seeking the right to marry, and the right of their children not to have their families branded as inferior.

Those briefs were signed by hundreds of Iowans including former Lieutenant Governors Joy Corning and Sally Pederson.

Iowa is now the first Midwestern state to allow gay marriage and is one of only three nationwide to allow same-sex couples to marry.