First of all, there need not be. The fact that there is no evidence for fairies does not mean there are no fairies. In the absence of any evidence against fairies - i.e. - one way or the other, we must adopt that wonderful position, "I don't know." So, even if there were no conceivable way in which life could have come about naturally, you would have to have positive evidence that life was created by god to say that. By which point, you've proven god anyway.
But I suggest you look up modern abiogenesis hypotheses. I believe the RNA world is quite plausible, although modern scientists believe it unlikely. From what I gather, current belief is that the first bits of life were amino acids (shown to be produced naturally in conditions like those of the early earth) which then assembled into a protein that could obtain energy from other organic molecules that would be lying around (methane, for example) and went on to replicate (by the same process of random polymerisation)
All this is entirely plausible. And so you have even less justification in leaping in, frothing, with "GODDIDIT." Even if there were no evidence for this view, it doesn't matter - since we have an alternative, no evidence for either means "I don't know."