Seriously, this article at LiveScience purports that household upbringing is mostly credited with the idea that scientists are less religious than the general population. It's a small study--about 1500 scientists. Now wait until you read this part:
I wonder if they stuck with the hard sciences (physics, chemistry, biology) what the percentages would be. There is a huge difference between people who have to use surveys and statistics, and people who are up to their necks in equations and scientific experiments.
Specifically, the survey contacted researchers specializing in physics, chemistry, biology, sociology, economics, political science, psychology and other fields.