Alan Chambers has issued a detailed apology on his own website, which at the time of this writing has crashed. The apology is reposted in the Buzzfeed link above.
Specifically, Chambers has renounced his beliefs that sexual orientation can be changed, that LGBT people are not acceptable to God, and he has renounced his opposition to same-sex marriage and other rights.
He has not, he says, renounced his own belief that (I'm paraphrasing) same-sex marriage is God's best plan for humanity. He is still a theological conservative. But, in his own words,
"I don't really know what to think, honestly, when it comes to gay marriage. But I also don't think anybody needs me to have a position. People have a right to live their lives as they see fit. If a friend or family member who is gay or lesbian invites me to be a part of their special day, I'm going to go and be a part of that because I love them. It doesn't matter if I endorse or condone something--that's not my right."And elsewhere:
“I cannot apologize for my deeply held biblical beliefs about the boundaries I see in scripture surrounding sex, but I will exercise my beliefs with great care and respect for those who do not share them. I cannot apologize for my beliefs about marriage. But I do not have any desire to fight you on your beliefs or the rights that you seek.”And that's all right. Folks on my side of the issue: please accept that he is where he is. I disagree with his theological position (i.e. I strongly support same-sex marriage and I think that it is God's will that same-sex couples should get marry when they are ready). But for religious folks, our relationship to God is also very, very important. He has said that he disagrees with same sex marriage, and that also he can no longer publicly oppose it. It is no longer clear that he thinks of homosexuality as a sin. It's clear that he has accepted the truth about homosexuality (that it's a normal variation and that it does not place people in jeopardy per se). This is what I would think if I were a theological conservative. He has also apologized publicly, and thus helped further undermine the position that sexual orientation can and should be changed. Thank God he did and thank God he is where he is.