There seems to be a difference between “we don’t know, therefore God did it” and “given our scientific knowledge, X seems highly implausible under the assumptions of metaphysical/methodological naturalism”. In any case, as Christians we believe miracle explanations are sometimes the best explanation (as in the resurrection for instance). Some may believe a miracle may be the best explanation for the beginning of life. I agree that these would not be good reasons to base one’s entire Christian worldview off of. Still, when are we warranted in inferring a miracle or supernatural event?