"If you're a real scientist, you can't be an atheist. Because our scientific methodology doesn't give us evidence for or against God, you can't be an atheist."
This is such a fundamental misunderstanding that it's hard to believe an educated person could fall for it. Science can't prove the non-existence of gods or ghosts or anything supernatural. But then again, science can't disprove the existence of Russell's Teapot:
If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in an elliptical orbit, nobody would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes. But if I were to go on to say that, since my assertion cannot be disproved, it is an intolerable presumption on the part of human reason to doubt it, I should rightly be thought to be talking nonsense.
In other words, atheists don't believe that the existence of god is scientifically disproved in any formal way. They just realise that there is no scientific evidence for the existence of god (and that's not for lack of trying!). The non-existence of god is deduced from the lack of direct evidence, and the multitude of indirect evidence. For example, we know that human beings around the world have a remarkable capacity for inventing gods that are clearly bogus - cargo cults, anyone?
We can't prove that god doesn't exist, but that doesn't mean we should take the idea seriously. The balance of probabilities is so far tilted in favour of non-existence, that to live your life on any other basis would just be unreasonable. And that's what atheism is about - it means living a life without god.