No reason. I don't believe in creationism but there's no reason it can't exist alongside evolution because evolution doesn't even try to explain the formation of life, just what happens to it afterward. Unless you're a crazy person and believe the earth to be 6,000 years old, like my brother does. He's an idiot. I can't believe we share genetic code. I agree with both of you that they can co-exist. But I would note that the main evidence for creationism is the Old Testament, and no one seems to know exactly who came up with the concept. The problem in creationism arise from the literal interpretation of the Bible, that insists in seven days. for the Creation. Once you remove that, and take 7 days as seven (and seven in the Biblical sense, as many) as seven periods, there is plenty of room for evolution to fin into the Biblical story. That is why Catholicism, that does not interpret the Bible literally, has no major problems with evolution. But the Churches that take the Bible literally (certain Evangelical Churches, for example) they do. Regarding on how Biochemistry started, there are certain explanations. Under the primitive earth conditions, it is possible to synthesize urea and a few aminoacids from inorganic forms of nitrogen. Once you have nitrogen in organic molecules (like aminoacids, and urea), provided there is some water, it can go from there. Mind that we are talking here of periods of hundred of millions of years. How did we get from baseball to here? The thing is that a very vocal minority of those who believe in creation actually believe in a literal 7 days. Many of those who believe in creation do not believe in an Earth that is only aged ~10,000 years. It's akin to politics (to bring it back to the original topic of the thread), where you see extremists on the liberal and conservative sides that make a heck of a lot of noise, but the large majority of the country sits between those extremes, not in them. I certainly don't believe every liberal wants to take away my hunting rifle, and I don't believe every conservative wants to have 3,408 automatic weapons per household (to pick one particular issue), but that's the word we hear because those are the loudest talkers.