Conception in zero gee

[AndrewL]

I have heard it claimed that conception in zero gravity is impossible. Ok, maybe not the conception stage, but apparantly there is a cruicial stage early in zygote formation that requires a gravitational gradient to occur - in microgravity you get a nonviable zygote that doesn’t develop further.

Does anybody know if this is true or not?

[Whack-a-Mole]

The answer seems to be we do not know yet. A couple of studies have been done on sperm in space but neither included actual fertilization and just focused on sperm motility. That zero-g has an effect on sperm seems without doubt. They swim faster for one thing (good news for fertilization) but further study suggested that some enzymes necessary to the whole process are adversely affected in zero-g. Bottom line is all they really know at this point is that they need to study it some more. Imagine the lucky astronauts who get to be the first to give this one a try!

According to Joseph Tash, a NASA-supported physiologist at the University of Kansas Medical Centre, sperm behave differently in the near-weightless environment of space than they do on Earth. Whether these changes will impair or aid fertility, he doesn’t yet know. But, says Tash, it’s becoming increasingly clear that in outer space, fertilisation - of humans, of animals, and even of plants - will very likely be affected.

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The tiny cells appeared to move better in a low gravity environment - good news, it seemed, for fertilisation, which is closely tied to sperm motility. Perhaps making babies would actually be easier in space!

But, says Tash, who has studied the sperm of sea urchins on board NASA shuttle flights, it’s not so simple.

<snip>

Although his results may explain why sperm move faster in space, they don’t necessarily imply that fertilisation will be easier. After all, if one enzyme (protein phosphatase) isn’t activated properly perhaps others will be affected, too. Many enzyme reactions play a role in the fertilisation process: for example, to ready the sperm to insert the DNA into the egg. Says Tash: if enzyme processes are being altered by gravity - and they are - you can’t even guess at the effect on fertilisation until you’ve studied more than just sperm movement.

<snip>

“For NASA,” says Tash, “the basic underlying question is: Do changes in gravitational force affect the ability of species to reproduce?” Increasingly, the answer seems to be yes. “It’s an area,” he says, “that requires a lot more attention.”

SOURCE: Floating Fertility