Space Travel May Make It Harder to Have Kids Sperm, egg counts fall in lab animals By Kevin Spak, Newser Staff Posted Jan 5, 2011 2:29 PM CST 7 comments Comments An astronaut is seen during a spacewalk in this file photo. (AP Photo/NASA) (Newser) – If you’re intent on having kids, you might want to cancel that vacation to Mars you’ve got penciled in. Research from a University of Kansas biologist suggests that long-term space travel might leave people “reproductively compromised,” the Kansas City Star reports. In tests on space-traveling and laboratory rodents, researcher Joe Tash has found that prolonged exposure to low gravity causes ovary cells to wither and sperm counts to plummet. “We have tantalizing data that require more rigorous investigation,” Tash says. “It’s unfortunate that we’re discovering this just as the shuttle program is winding down.” He’ll have some mice aboard one of the final space shuttle flights in February, and after that will have to rely on commercial and foreign spacecraft. Zero gravity is already known to weaken the body’s muscles, immune system, and healing capabilities, but NASA’s devised means of counteracting it, most notably zero-gravity exercises. Hmm. So what kind of exercises might help maintain reproductive health? “That’s a good question,” one NASA biologist said, with a sheepish laugh.