A recent study published in Science Advances reveals that the Japanese researchers found that the mouse sperm which was exposed to high levels of cosmic radiation for nearly six years has produced a large brood of healthy, unremarkable "space pups."
No signs of Mousezillas or rodent Hulks have been observed so far.
The study reveals that the sperm was stored in the International Space Station in freeze-dried form. When it was brought back to Earth and rehydrated, it gave birth to 168 young, free of genetic defects.