Stephen Crabb has insisted he does not think being gay is a "sin" and dismissed the suggestion he supports gay-cure therapy as "entirely fabricated".
The Conservative Party leadership candidate voted against gay marriage but said today he was "happy" with its legalisation.
"I totally, totally support equal marriage in law and I am playing my part in Government now to contribute and foster a climate and culture of tolerance and respect," the work and pensions secretary told BBC Radio 4's Today programme this morning.
"I don’t want anybody in society feeling second best, whether that’s to do with the colour of their skin or their sexuality."
Crabb has been dogged by the suggestion he supports so-called gay cure therapy ever since he employed interns in his parliamentary office, as did other MPs, via the Christian Action Research and Education (CARE) group.
CARE has argued people can become "ex-gay" and referred to gay people as "sexually broken".
Crabb this morning distanced himself from the group. "I don’t know whether it is a view that CARE holds; if it is, I don’t agree with it," he said.
"The idea that being gay is something to be cured, that is reprehensible. That’s never been part of anything that I believe and it’s certainly not part of my Christian outlook."
He added: "I don’t believe that being gay is a sin, I don’t believe it is something to be cured, I’ve never said anything like that.
"The quote that I think you’re referring to that has been circulating on social media was entirely fabricated. I have never said anything at all to suggest that I have ever believed that I endorse gay cure therapy. This is complete falsehood spread by political opponents."
Conservative MPs will today cast their votes in the first ballot in the leadership race.
Home secretary Theresa May is seen as the frontrunner, followed by energy minister Andrea Leadsom.
Crabb is also joined in the race by justice secretary Michael Gove and former defence secretary Liam Fox.