David Matheson said he regrets perpetuating the idea that being gay is a disorder. “It is horrifying to think that I was part of a system that held people like me down,” he said in an exclusive interview for Channel 4 News.

Matheson, a protege of the late NARTH (National Association for Research and Therapy of Homosexuality) therapist Joseph Nicolosi and the founder of the Mormon ‘ex-gay' therapy group The Center for Gender Wholeness and the Journey Into Manhood ‘ex-gay' retreat, has quit the “ex-gay” movement and is now dating men exclusively.

Matheson, 57, admitted the practice which nearly 700,000 Americans have undergone, “is not only built on a harmful philosophy, but should be banned.”

“I regret my part in perpetuating those ideas,” Matheson said. “Perpetuating the idea that being gay is a pathology, a disorder. Perpetuating the idea that God is not okay with people being gay. That, I regret. I mean, it held me back and it held lot of other people back.”

Asked if he was sorry for the hurt and damage that he caused, Matheson said: “Are you kidding? I mean it is horrifying to think that I was part of a system that held people like me down and I've had some conversations with other people who have been harmed by it. It creates a lot of sorrow.”

Back in January, Wayne Besen of Truth Wins Out got word of Matheson's via a private Facebook group run by Matheson's Journey Into Manhood director Rich Wyler who told the group “[Matheson] has gone from bisexuality to exclusively gay.”

Matheson spoke with Besen and said: “My time in a straight marriage and in the “ex-gay” world was genuine and sincere and a rich blessing to me. I remember most of it with fondness and gratitude for the joy and growth it caused in me and many others. But I had stopped growing and was starting to die. So I've embarked on a new life-giving path that has already started a whole new growth process. I wasn't faking it all those years. I'm not renouncing my past work or my LDS faith. And I'm not condemning mixed-orientation marriages. I continue to support the rights of individuals to choose how they will respond to their sexual attractions and identity. With that freedom, I am now choosing to pursue life as a gay man.”

The report is joined with a video from New York by Chaim Levin, who twice attended retreats co-founded by David Matheson.

Watch the full video below.