In a phone interview Thursday from Orlando, Fla., where Exodus has its headquarters, Mr. Chambers amplified on the views that have stirred so much controversy. He said that virtually every “ex-gay” he has ever met still harbors homosexual cravings, himself included. Mr. Chambers, who left the gay life to marry and have two children, said that gay Christians like himself faced a lifelong spiritual struggle to avoid sin and should not be afraid to admit it.

He said Exodus could no longer condone reparative therapy, which blames homosexuality on emotional scars in childhood and claims to reshape the psyche. And in a theological departure that has caused the sharpest reaction from conservative pastors, Mr. Chambers said he believed that those who persist in homosexual behavior could still be saved by Christ and go to heaven.

Only a few years ago, Mr. Chambers was featured in advertisements along with his wife, Leslie, saying, “Change is possible.” But now, he said in the interview, “Exodus needs to move beyond that slogan.”

“I believe that any sexual expression outside of heterosexual, monogamous marriage is sinful according to the Bible,” Mr. Chambers emphasized. “But we’ve been asking people with same-sex attractions to overcome something in a way that we don’t ask of anyone else,” he said, noting that Christians with other sins, whether heterosexual lust, pornography, pride or gluttony, do not receive the same blanket condemnations.

Mr. Chambers’s comments come at a time of widening acceptance of homosexuality and denunciation of reparative therapy by professional societies that say it is based on faulty science and potentially harmful.