It's a guided process in a lab - who knows what the conditions were back then.
I tend to try to be evidence driven without trying to fill in the gaps to match any preconceptions I may or may not have.
I have an open mind and can admit that it's possible that it was guided at the beginning. I think that solution raises a lot more questions than it answers though.
With that in mind I tend to fall on the side of a spontaneous initiation of life. Ok, it might be improbable but so is winning the lottery, yet someone wins it every week.