The Archbishop of Canterbury has said that his stance against gay marriage could be seen as "wicked".
While the Most Rev Justin Welby said he would stand by his decision to vote against same-sex marriage legislation, he said that opposing the move could be seen by some as akin to "racism and other forms of gross and atrocious injustice".
Speaking at the official opening of the Evangelical Alliance's new premises in King's Cross, London, he said that today's society had evolving views about sexuality and many younger people thought that opposition to gay marriage was "plain wrong".
The Marriage (Same-Sex Couples) Act received royal assent in July and gay couples in England and Wales will be able to wed at some point next year.
The legislation had a tortuous passage through Parliament, with staunch opposition from many conservative backbenchers and religious groups.
The Archbishop, who voted against the legislation, said: "What I voted against was what seemed to me to be the rewriting the nature of marriage in a way that I have to say within the Christian tradition and within scripture and within our understanding is not the right way to deal with the very important issues that were attempted to be dealt with in that Bill.
"The Bill was clearly, quite rightly, trying to deal with issues of homophobia in our society.
"As I said at the time in the House of Lords, the Church has not been good at dealing with homophobia - it has at times, as gods people, either implicitly or explicitly supported it and we have to be really, really repentant about that because it is utterly and totally wrong.
"But that doesn't mean that redefining marriage is the right way forward.
"That discussion is continuing and the Church is deeply and profoundly divided over the way forward on it.
"I am absolutely committed not to exclude people who have a different view from me, I am also absolutely committed to listening very carefully to them.
"If the same thing happened again I would vote the same way as I did then but I am continuing to think and listen very carefully as to how in our society today we respond to what is the most rapid cultural change in this area than there has been for a very long time.
"We have seen changes in the idea about sexuality, sexual behaviour.
"We have to face the fact that the vast majority of people under 35 not only think that what we're saying is incomprehensible but also think that we're plain wrong and wicked and equate it to racism and other forms of gross and atrocious injustice.
"We have to be real about that.
"I haven't got the answer one way or the other until my mind is clear on this.
"I'm not going to get into the trenches."
He has previously said that there has been a "revolution" in attitudes to homosexuality, particularly among young people, and has said that the Church of England needs to acknowledge the change in opinions.
Ben Summerskill, chief executive of gay rights charity Stonewall, said: "It is a tiny bit rich to say he has great sympathy for gay people when in the 10 years since the introduction of civil partnerships the Church has doggedly refused to bless people's long term partnerships even though they are happy to have services for pets and even canals.
"Polling conducted by Stonewall found people under 45 are overwhelmingly in support of gay marriage.
"Meanwhile, church attendances continue to fall, which is very sad for lots of people, (but) that is not going to change if it doesn't concur with half of the population."
Benjamin Cohen, founder of campaign group Out4Marriage and publisher of PinkNews, added: "It is welcome that the Archbishop of Canterbury has recognised that the majority of people under the age of 35 do not consider same-sex relationships as anything other than normal.
"They do see that attacking gay people for the gender of the person that they love is as evil and incomprehensible as attacking someone for being born black or disabled. People don't chose to be gay just like they don't chose their race.
"I would not argue that the Archbishop's stance was 'wicked'. All the way through the debate on same-sex marriage, those of us in favour of the change always maintained that churches, synagogues and mosques should be free not to opt-in to same-sex marriage. This is their right. Just as it is the right of the younger generations to question the relevance of these institutions if they reject a change in the law that most young people think is nothing more than equality."