Hmmm... let me see if I understand. You're saying you don't believe in
creation. And you're looking for
another scientific reason for why we are here. Which is legitimate, I guess.
"Science", the entity, doesn't have more that one notion of how we got here. It "believes" in evolution. Just like some people believe in God, I guess. We could go on about the differences, but we won't, because it's irrelevant right now. When science considers something proven 'beyond reasonable doubt', for it's own purposes, it accepts it as true. Evolution cannot be proven, as has been debated many times on E2. However, we see evolution actively taking place in bacteria, we have fossils, etc. That's good enough for us. So of course research in evolution accepts the existence of evolution. Research in cancer accepts the existence of cancer.
Of course, science could be wrong. This won't be the first time it's happened. Newton was 'wrong', and science accepted his 3 laws. Science believed Newton for many years, until Einstein came along and disproved him. Hell, the 'fact' that the sun revolves around the world was only disproved in the previous millenium!
So it could be that someone will come along with a better explanation. But right now, evolution is what we have. And it's good enough for me.