
Sperm Lose Direction in Microgravity, Raising Spaceflight Reproduction Concerns
Researchers used a 3D clinostat to simulate microgravity and tested human, pig, and mouse sperm in a channel resembling the female reproductive tract; they found a significant drop in the number of sperm reaching the egg under microgravity, not due to motor changes but impaired direction sensing; fertilization dropped about 30% after four hours of exposure, with longer exposure causing delays and fewer embryos; progesterone could still guide sperm, indicating chemotaxis remains important; the findings, published in Communications Biology, imply spaceflight could affect reproductive outcomes in humans and livestock, highlighting the need for further research.






