When asked on ABC's Q&A on Monday night how he could claim to be a Christian but keep "chopping and changing" his beliefs on gay marriage, Mr Rudd said it was "just wrong" to think people choose their sexuality. "They are gay if they are born gay," he said bluntly. Matt Prater: questioned Prime Minister Kevin Rudd on his gay marriage stance. Credit:Screen grab, Q&A "You don't decide at some later stage in life to be one thing or the other. It is how people are built and therefore the idea that this is somehow an abnormal condition is just wrong, I don't get that. I think that is just a completely ill-founded view." Mr Rudd said he made a decision a few months ago to change his position on gay marriage after reflecting for "many, many months and years" and concluding in his "informed conscience and Christian conscience" that it was the right thing to do.

He said that, once he accepted that humans don't choose to be gay, he formed the belief that it was not right to deny certain people the opportunity for legal recognition in their relationship. At one point, he challenged the pastor to further clarify his view, demanding he say whether he thought homosexuality was "abnormal". Prime Minister Kevin Rudd: his answer has caused a broad spectrum of reactions. Credit:Screen grab, Q&A "I just believe in what the Bible says and I'm just curious for you, Kevin, if you call yourself a Christian, why don't you believe the words of Jesus in the Bible?" Mr Rudd responded: "Well, mate, if I was going to have that view, the Bible also says that slavery is a natural condition."

It was met with loud applause from the audience. Former president of the Australian Medical Association and outspoken gay advocate Doctor Kerryn Phelps said Mr Rudd's impassioned response was a "historical moment in Australian politics". "That's a monumental shift . . . supporting marriage equality as a career move," she tweeted. Another Twitter user, @schtang, said "that response by Rudd to the pastor has to be the answer of the century in regards to marriage equality".

Gay and lesbian advocacy group Australian Marriage Equality said Mr Rudd's "unprecedented response" marked a historic moment in the debate and would resonate with Australians. "It is unprecedented in Australian history for a Prime Minister to give such a strong defence of equality for gay people, and it was made all the more compelling because it was from a Christian perspective," national director Rodney Croome said. "Mr Rudd gave a moral and spiritual urgency to marriage equality that will resonate with many Australians, including many Australians Christians, and which marks a historic moment in the debate." On the Gay Star News website, comments ranged from "Why can't all Christians be like this?" to "Fantastic and eloquent".

However, some viewers also accused the Prime Minister of bullying. News Corp columnist Tim Blair said that personalising the exchange and demanding to know if his questioner believes “homosexuality is abnormal” was bullying. "It's bullying, but it plays well to a whooping Q&A crowd who don't appreciate that Rudd and the targeted audience member were on the same side just 107 days ago," he said. Mr Rudd finished his response by referring to the New Testament.

Loading "The human condition and social conditions change," he said. "What is the fundamental principle of the New Testament? It is one of universal love. If we get obsessed with a particular definition for that through sexuality then I think we're missing the centrality of what the gospel... is all about. And therefore I go back to my question, if you think homosexuality is an unnatural condition then frankly I cannot agree with you based on any element of the science."