An anonymous reader quotes a report from The Guardian: Reproduction may be possible in space, Japanese researchers have said, after freeze-dried sperm stored on the International Space Station for nine months produced healthy offspring. The scientists said their findings could have significant ramifications for human settlements in space, which they consider "likely." The average daily radiation dose on the ISS is about 100 times stronger than that on Earth, posing a threat of serious reproductive problems for any space-dwelling organism. But mouse sperm stored on the ISS for 288 days from August 2013 to May 2014, then returned to Earth, fertilized in vitro and transferred into female mice, produced healthy offspring. The space-preserved samples showed evidence of slightly increased DNA damage compared with control samples preserved on Earth, but this was found to be largely repaired in embryos following fertilization. The birth rate and sex ratio of pups derived from the sperm stored in space was comparable to those of pups derived from the control samples. Subsequent whole genome analysis revealed only minor differences, and the pups developed into adults with normal fertility. The study was published in the proceedings of the U.S. National Academy of Sciences on Monday.