Male mice that spent more than a month in space were able to successfully reproduce back on Earth, a study has found, the first evidence of how space travel affects reproduction in mammals.
There have been some signs that spending time in space could negatively affect sperm, including radiation damage seen in freeze-dried mouse sperm that spent nine months in outer space, and decreased sperm counts in rats that spent 13 days in orbit.
The research examined 12 male mice who spent 35 days aboard the International Space Station (ISS) in specially designed cages. Some of the mice experienced the weightlessness of microgravity, while others were in cages designed to offer artificial gravity.
Upon their return to Earth, the researchers used sperm from the mice to fertilize eggs from female mice who had not experienced space travel, and found the astronaut rodents produced healthy offspring.
The team, led by Masahito Ikawa, a professor at Osaka University, also examined the reproductive organs of the space-travelling mice, and checked their offspring for any signs that their parentage had negative effects.
"We conclude that short-term stays in outer space do not cause overt defects in the physiological function of male reproductive organs, sperm function and offspring viability," says the study published Tuesday in the journal Scientific Reports.
The research is only a first foray however, and does not necessarily indicate how the reproductive systems of human — or indeed female mice are affected by space travel.