Andrew Brown has a new blog on the Guardian. Go and discuss this with him:
"if there is no God, then we cannot be made in his image, and we cannot be his children: in that case there is nothing which it is wrong to do to a human being simply because they are a human being. Note: this isn't a claim that no atheists can believe in human rights. That would be absurd. It is a claim that the atheist who believes in human rights must believe that they are no more than a socially constructed reality and that if no one believed in them, they would not exist. Otherwise, Rowan would say, if you reach to some standard of humanity independent of actual humans, you are reaching for something that makes sense of a lot of talk about God."
(He's channelling Rowan)