In the 1930's it was declared unlawful that a teacher were to lecture / teach evolution. Creationism was strictly enforced in schools. During this time period most Americans were conservative protestant who strictly opposed evolution. These people were firm believers in the bible and the story of Genesis. When Charles Darwin came up with his book On the Origin of Species by Means of Natural Selection, the religious protestants felt threatened. His theory made creationism seam wrong and unimportant to some people. His theory of natural selection and survival of the fittest was/is logically correct and in my opinion it made creationism appear to be wrong. Therefore the protestant government fought against the teaching of evolution.
There were several cases against the teaching of evolution for example the 1925 scopes "monkey" trail. --> The Social and Legal Dimensions of the Evolution Debate in the U.S <--
Later some states considered teaching "intelligent design" which is : life is too complex to have developed without the intervention of an outside, possibly divine force. And also because Darwins findings are nothing but a theory (not a fact) some areas approached evolution with an open mind and to have critical consideration. This lead to some successful debates upon evolution.
I believe evolution should be taught in schools because public non religious school should not preach religion upon students. I understand if you go to a catholic or christian school because that is a religious school that you have chosen to attend, and you are putting yourself in a religious environment where religion is legally preached.
I am not a religious person so I do not believe in creationism. Evolution makes more sense to me, in addition I attend a public school where religion is not taught or should be taught.