According to the paper, “NASA has identified five hazards of space travel: space radiation; isolation and confinement; distance from Earth; gravity (or lack of gravity); and hostile environments.” And while we already know the human body can adapt to space travel in some ways, “including cardiovascular, fluid balance, and vestibular systems,” we also know “bone density, calcium metabolism, and reproductive function, exhibit incomplete or delayed recovery. Additionally, there’s limited evidence that suggests space travel could negatively affect “hormonal signalling and gamete quality in ways that may not be corrected fully upon return to Earth.”
For those who don’t return, though, attempting to reproduce off-planet could be even riskier. As Palmer told Gizmodo, “Over the long term, prolonged exposure to these conditions may cause cumulative reproductive damage and heritable risks, including epigenetic changes that alter gene expression and potentially affect fertility and the health of future offspring.”
The good news is, we know a decent amount about how radiation exposure affects the human body. The bad news is, we still don’t know enough, and what we do know suggests it can negatively impact reproductive health, making it both harder to successfully reproduce and more likely any resulting child could be born with health defects. The long-term effects of living in microgravity are less well-understood, but based on what we do know, “[a]lterations in gravity remove or change a fundamental mechanical cue, influencing hormonal regulation, gametogenesis and early embryonic development in ways that are still not fully understood.”
“Space radiation can damage DNA, disrupt gamete formation, and raise cancer risk, while microgravity interferes with hormonal regulation, gamete quality, and embryonic development,” Palmer told Gizmodo. In light of how risky off-planet reproduction could be, Palmer also emphasized the need to develop “clear ethical guidelines that prioritize informed consent, transparency, gender equity, and the protection of future offspring.” Thankfully, if anyone understands clear ethical guidelines, it’s Elon Musk.
