Preceding the 200th anniversary of the birth of Charles Darwin, Gallup did a poll showing that 39% of Americans believe in the theory of evolution and 25% say they do not.
While I understand the intent of this poll and I realize they are professionals, I have a problem with the way the question is phrased. "Do you believe in the theory of evolution?" is like asking "Do you believe in the theory of gravity?" I think it misrepresents the context of the word theory. This form of the question makes theory sound like it's a "contemplation or speculation" as opposed to "a coherent group of general propositions used as principles of explanation for a class of phenomena." (Definitions shamelessly stolen from dictionary.com.) The poll found:
Americans who have lower levels of formal education are significantly less likely than others to be able to identity Darwin with his theory, and to have an opinion on it either way. Still, the evidence is clear that even to this day, Americans' religious beliefs are a significant predictor of their attitudes toward Darwin's theory. Those who attend church most often are the least likely to believe in evolution, and most likely to say they do not believe in it.
That's not to say all church goers are ignorant of science, but that the level of religiosity is a factor in accepting whether the scientific explanations behind evolution are valid or true. In science, a current theory is a theory that has no equally acceptable or more acceptable alternative theory, and has survived attempts at falsification. That means there have been no observations made which contradict it to this point and every observation ever made either supports the current theory or at least does not falsify it by contradicting it completely.
Last year the National Academy of Sciences published a book entitled Science, Evolution, and Creationism (you can read it online, create a free account and download the entire text in PDF or order a copy) in which they found:
Religious denominations that do not accept the occurrence of evolution tend to be those that believe in strictly literal interpretations of religious texts.
Sort of reminds me of the guy in Jurassic Park the priest was talking about last Sunday who denied reality by hiding in a bathroom and got eaten by the T-Rex.