well, the really interesting question is:
what was before the "big bang", if there was such thing.
on the one hand, without matter there can not be time... so there was no "before"... but was the universe created out of nothing? impossible, you would think...
many many unsolved questions... and yet, i believe in evolution (to get back on topic). and the egg: well, first there was an egg, then the chicken, because as mentioned before, some "non-chicken creature" must have laid an egg.