Teaching Evolution, and Creationism.?

If evolution is only a theory. (which it is. There is no proof that man came from any other creture. We are not DNA related to any other creature that we know of.) And evolution can be taught in public schools then why can't creationism? (Also a theory) Creationism has nothing to do with religion or cristianity, So the argument of seperation of church and state is void. Don't you think that the Theories should recieve equel billing as well as other theories of the planets origin such as that of the American Indians who believe that all the world is connected in a cycle, and was created by a great spirit (not a god)that lives in everything. Shouldn't all theories be given the same time in schools? Since some believe that a superior being is what created the world,and others believe that it was just a big bang,and we evolved. but there is really no proof of either only faith in each one's theory. So do you think they should both be taught or not? and why?