After this experiment, the cells showed vast differences on the molecular level, with 64 percent of their proteins differing from those grown under normal gravity. Specifically, these microgravity-exposed cells generated more proteins that degrade bone and fewer proteins with antioxidant effects. Antioxidants protect against reactive oxidants that can damage DNA.
Microgravity also influenced levels of a broad range of other proteins. These include those involved in cell division, the immune system, the muscle and skeletal systems, calcium levels within cells, and cell motility.
These findings in embryonic stem cells may not bode well for attempts at procreation in microgravity.