Japanese researchers behind the new work... wanted to know how space radiation affects fertility in mammals. Radiation can damage the DNA within cells, causing mutations... Environments on Earth with heavy radiation exposure can cause defects in the offspring of animals. Space radiation in particular has been a major concern for countries like the U.S. and Japan that have sent many astronauts on lengthy missions into low Earth orbit. Farther space destinations are also on the horizon. NASA and other space agencies are developing systems that could support humans on monthslong journeys to other solar system destinations such as the moon...