To test these effects, the researchers artificially fertilized mouse eggs with sperm that had been stored inside a three-dimensional clinostat, a machine that mimics weightlessness by rotating objects in such a way that the effects of gravity are spread in every direction.
Fertilization took place normally, suggesting that microgravity hadn’t harmed the sperm. But as the embryos continued to develop inside the clinostat, many developed problems. Their cells had trouble dividing and maturing.
There were some baby mice produced after the embryos were implanted, but not many survived compared to a control group. Link -via Digg