Suppose that there's a gene that makes you gay if you were bottle-fed but that has some completely different effect if you were breast-fed. So in the days before bottles were invented that gene would not have manifested itself as gay behavior, but now that bottles are common it can do so.

I find that religion really does motivate people to do horrible things because they have this passionate faith in whatever their religion happens to be, and it teaches them that the other religion is the wrong one.

We have the power to defy the selfish genes of our birth and, if necessary, the selfish memes of our indoctrination. We can even discuss ways of deliberately cultivating and nurturing pure, disinterested altruism - something that has no place in nature, something that has never existed before in the whole history of the world. We are built as gene machines and cultured as meme machines, but we have the power to turn against our creators. We, alone on earth, can rebel against the tyranny of the selfish replicators.

Creationists and Holocaust deniers are both very similar - both are denying what is a perfectly manifest fact. In the case of Holocaust deniers it's more recent history, but in both cases the evidence - in favour of the Holocaust and evolution - is simply overwhelming. That doesn't mean they are morally or politically equivalent. But they are equivalent in denying history.

I really, really would like to see religion go away altogether.

I like to think 'The God Delusion' is a humorous book. I think, actually, it's full of laughs. And people who describe it as a polarizing book or as an aggressive book, it's just that very often they haven't read it.

God's existence is either true or not. But calling it a scientific question implies that the tools of science can provide the answer.