Embryonic stem cells behave very differently outside the pull of Earth’s gravity.

Any future astronauts here who are hoping to make the first space baby might want to think again – embryonic stem cells don’t act the same way in zero gravity, making successful procreation in space almost impossible.

We already know that full-grown adults suffer harmful consequences the longer they stay in microgravity, as prolonged living in zero-G causes muscles and bones to weaken and an irregular heartbeat. But the dangers also operate on much tinier scales as well, as a team of Australian researchers have now discovered. Microgravity tampers with stem cells, the building blocks of all other cells in our body and a vital repair system.

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