Let's start at the beginning. I think the argument goes, to get DNA, you need proteins, but you can't get proteins without DNA. Could RNA create proteins then? Lots of effort has shown that nucleotides can be synthesized. But these are randomly arranged and don't code for anything. So far then, the evidence suggests it is impossible for the first ever cell to form naturally.
Firstly (and purely logically), not having a current explanation does not mean that something is impossible.
Secondly, what we do have is copious evidence that simple life started on earth at a certain time and under certain conditions and then evolved into more the more complex and diverse life we have today. As has already been pointed out, the idea that a god created the universe that could just about but not quite do the job of making humans, and it then needed some extra god-magic to kick life off or nudge evolution along is totally illogical.
Thirdly, what you need to get natural selection going is replication with variation and inheritance, which could be something as simple a single strand of RNA, like, for example, this:
NNNNNNUGCUCGAUUGGUAACAGUUUGAAUGGGUUGAAGUAU–GAGACCGNNNNNN
Where the 'N's are 'don't care' and the other letters are standard for RNA (it's is called RC3). Research is ongoing (for example:
How RNA formed at the origins of life) but we have absolutely no reason to conclude that abiogenesis is
impossible, and, as I keep on pointing out to Alan, you'd really need to claim to be
omniscient about nature to be sure that something was impossible through natural means.
The start of life may be very probable (which is suggested by the fact that it started on Earth pretty much as soon as the conditions were suitable to sustain it) or very improbable - we only know that it happened at least once and the universe is very, very big, with lots of chances, as far as we can tell.