Hi Jgnat,
"Without resorting to "God did it", is there a scientific explanation how the first life might have come to be?"
I have read The Spark of Life by Christopher Wills and Jeffery Bada plus several shorter articles on the subject. From all that I can tell the answer for now is we don't know. But that doesn't mean we don't anything at all. For example, I know this might seem obvious, but... we know life did not always exist on Earth. There was a time that Earth was completely sterile. We also know that in general "Origin of..." questions are very difficult when we lack examples of similar events. For example, we know the Earth is here and must have had some origin, but there are still some pretty big and unanswered questions about planetary formation. Such events just don't happen often enough closeby for us to figure them out. Likewise the origin of the universe itself is, to us, a single event in the very remote past that will probably always prevent us from knowing the exact how and why.
Some articles I have read suggest an RNA-only world likely existed before DNA. Indeed DNA is incredibly useful for stable storage and transmission of information across generations. But without translation via RNA it is rather useless to actual life function. Please, anyone more educated in this, don't hesitate to jump in and correct any mistake notions I might have. It is entirely possible I've misunderstood some that I've read on the subject.
We also know that all objects that are the result of intelligent design are not life-like, in that they don't self-replicate. A gopher hole is the result of ID, but the hole by itself doesn't reproduce. Likewise a TV is the result of ID, but again doesn't self-reproduce. It is of course possible that a sufficiently advanced intelligence could use ID to create a self-replicating system. In fact people are working on that (Lord help us if ever such things go amok). I think this difference between ID-systems and self-replicating systems is important to this argument, because... ID is invoked to overcome some barrier nature by itself could not overcome. But... one would assume the barrier would remain even after the initial creative act. Thus if one says, free oxygen would destroy initial life, it means the designer cannot just create life, but he must coddle it along to prevent a natural demise.
Alas, history shows natural demise of life forms is the general rule on earth. Even species that have managed to survive for millions of years, up and go extinct.
Finally, there is no reason to believe humans are special in this regard. Earth cannot last forever and this is the only viable place for us to live. Even if our ancestors were to find a way to leave Earth and live in a spaceship or on some distant planet, inevitably evolution would take over and such creatures would become a new species.
Cheers,
-Randy