The Coronation Street star slammed Church leaders who insist that same-sex unions will ruin society and the institution of marriage, saying that the Church should "move with the times".
Government leaders in the UK are currently considering plans to legalise gay marriage by 2015, which has sparked complaints from Church of England leaders.
Cotton told the Manchester Evening News: "I've heard many comments - from the craziest, most out of touch, lunatic clerics to the most sensible of Church representatives. Nothing surprises me any more. My view is simple - equality is equality is equality."
The 36-year-old actor went on to accuse the Church of being out of step with modern views.
He added: "If the Church is going to move forward and remain relevant, it has to move with the times. Young people, generally, couldn't give a damn if people are gay - they are resilient and accept it. It's not enough any more to say that the Church is set in its ways."
Cotton, who plays Sean Tully on Coronation Street, concluded by criticising the Church for weighing in on the subject at all, insisting it is a government matter.
"They can't have an appendix where there are stipulations on equality," he said. "What's illegal is determined by the state - not the Church."
Archbishop of Canterbury Dr Rowan Williams and Archbishop of York Dr John Sentamu have written to home secretary Theresa May in protest at the plans, saying that the decisions on gay marriage "have not been thought through and are not legally sound".