Microgravity Disrupts Sperm Navigation, Fertilization

Scientists at the University of Adelaide's Robinson Research Institute have uncovered significant challenges to human reproduction in space, revealing that microgravity disrupts sperm navigation and reduces fertilization rates in mammals. The study, published this week in the journal Communications Biology, simulated zero-gravity conditions on Earth and tested sperm from humans, mice, and pigs, showing that while sperm maintain their swimming ability, they struggle to orient themselves toward an egg.

Led by senior author Dr. Nicole McPherson, the research used a 3D clinostat device to rotate samples and mimic the weightlessness experienced in space. Researchers placed sperm into narrow channels designed to replicate the female reproductive tract, observing their progress under both normal and simulated microgravity. In normal gravity, sperm effectively followed chemical and physical cues to navigate the channels. However, without gravity, human and mouse sperm showed about a 50 percent reduction in successful navigation, tumbling erratically or moving without clear direction. Pig sperm exhibited similar disorientation. Dr. McPherson explained, "This is the first time we have...