A mammal is carried to birth in an artificial womb

The end point of taking birth out of the body: an animal that goes from a fertilised egg to a live birth with no mother at any stage. Nothing has done this. The two famous results are halves: in 2017 lambs taken from their mothers two thirds of the way through pregnancy lived for four weeks in a fluid-filled bag and were born from it; in 2021 mouse embryos grew in bottles from a few days old to about the midpoint of pregnancy. The gap between the two halves has not been bridged in any mammal, which is why this entry sits at the bottom of the ladder with a precise test.

What would count

A mammal develops from fertilisation, or at the latest from before the midpoint of its normal gestation, to a live birth entirely outside any body, and survives, in a peer-reviewed report. Support of a fetus taken from its mother late in pregnancy, however long, does not count.

Who settles it: Peer-reviewed reports; a company's claim counts only when the paper exists

Where it stands

Idea only. Not yet shown to work in any living animal, so there is no record to point at. Could move a stage within 5 to 20 years.

The last reading

Once a week every upgrade is read against the news, against what would count above. Open a line to see what that week held. Every reading of this upgrade is on this week's reading.

• 16 October 2026 Nothing new

  Nothing in the window. No animal has gone from fertilisation, or from before mid-gestation, to birth outside a body: the marsupial embryo work reported in January 2025 reached mid-gestation and mouse embryos stop at about day 11. A viral 2026 claim of a 'pregnancy robot' was debunked. The FDA's 2023 advisory meeting on late-pregnancy support devices concerns a different thing, which the test excludes.

Notes

The charter expected this leaf at shown in animals. The test above is stricter on purpose, because the words "carried to birth" promise the whole pregnancy and no animal result delivers it: the 2017 Philadelphia lambs entered the bag at 104 to 135 days of a 145-day gestation, and the 2021 Israeli mouse embryos stopped at day 11 of about 20. A company working on extinct-species revival has said it aims to have a mammal born fully outside a body, with no peer-reviewed result yet. Either half would be an entry of its own if John wants the partial results on the tree; the artificial womb for very premature babies, the human use of the 2017 work, is heading for trials and would belong on the Lifespan and repair branch.