In the Maher interview, he made a claim like all intelligent scientists are atheists, or you can't be an intelligent scientist without being atheistic. Then Maher said that Francis Collins, the head of the Genome Project, is a notable scientist that believes in God, and further in Christianity. Dawkins reacted firstly with a "well Collins was a manager of the project, not a scientist, and I don't think he adheres to biblical teachings." Maher says "yes he does." The Dawkins says "He does?! Then he is stupid!"
This was more than enough to turn me off. His work in this field is shoddy. I'm not familiar with his science, but maybe he's better at that.