Researchers examined the effects of microgravity on human, mouse, and pig cells using an apparatus that replicated the weightlessness of space. They discovered that sperm navigation was hampered by microgravity, but that this impairment could be partially reversed by high progesterone dosages. Microgravity for up to 24 hours also slowed the growth of pig and mouse embryos. The results demonstrate that reproductive processes are susceptible to variations in gravity as nations prepare for expeditions to the moon and Mars.
