It's a long way from the "womb tanks" of science fiction - but scientists in, of course, Scotland managed to keep eight extremely premature lambs alive for four weeks in an artificial womb - which is basically a plastic bag.
A very sophisticated plastic bag. The lambs are developing normally. The bag is filled with synthetic amniotic fluid and provides the lambs with oxygen and nourishment.
They're hoping to be able to use "womb bags" for extremely premature babies within a few years.
And it is the first step towards ectogenesis.