Reproduction stalls in zero gravity as sperm gets lost in space | Science | News
Reproducing in space will have to wait (Image: undefined)
Human sperm loses its navigational abilities in space, indicating that creating mini-astronauts on the Moon or Mars could prove to be quite challenging.
Fresh research from the University of Adelaide suggests reproductive material might require a form of sat-nav in microgravity, casting doubt on Elon Musk and his billionaire friends’ aspirations to one day colonise other planets.
In a pioneering lab study, scientists simulated weightlessness using a device that continuously flips cells to mimic zero-G conditions.
Sperm from three mammals, including humans, were subsequently sent squirming through a minuscule maze modelled on the female reproductive tract.
The results revealed significantly fewer sperm successfully navigating the labyrinth under simulated microgravity compared to under Earth’s normal gravitational pull.
Importantly, their swimming power didn’t diminish – their mobility remained consistent – suggesting it’s their navigation, not their propulsion, that becomes disoriented without gravity’s subtle cues.
However, there was a ray of hope for cosmic conception, according to the study published in Communications Biology, as when researchers introduced progesterone – the sex hormone released by the egg that assists in guiding sperm – more swimmers managed to overcome the zero-G disorientation.
This suggests the egg’s chemical signal may still prove effective, though the team acknowledges further research is required to establish how and when this assistance becomes active.
Senior author Dr Nicole McPherson, from Adelaide University’s Robinson Research Institute, stated: “This is the first time we have been able to show that gravity is an important factor in sperm’s ability to navigate through a channel like the reproductive tract.
Sperm lose their sense of direction in zero gravity (Image: undefined)
“We observed a significant reduction in the number of sperm that were able to successfully find their way through the chamber maze in microgravity conditions compared to normal gravity.
“This was experienced right across all models, despite no changes to the way sperm physically move. This indicates that their loss of direction was not due to a change in motility but other elements.”
It’s not solely sperm experiencing difficulties. In animal studies, brief exposure to simulated microgravity during fertilisation severely impacted early development: mouse eggs experienced approximately a 30% decline in successful fertilisation after merely four hours in zero-G conditions.
Extended exposure exacerbates matters further, with developmental delays and reduced cell formation in the foetus. Nevertheless, numerous healthy embryos were produced – encouraging news for future colonisation, while also serving as a stark reminder that reproduction beyond Earth is far from simple.
The initiative collaborated with Adelaide’s Andy Thomas Centre for Space Resources, where researchers are concentrating on the practicalities of sustained off-world habitation. Associate Professor John Culton said: “As we progress toward becoming a spacefaring or multi-planetary species, understanding how microgravity affects the earliest stages of reproduction is critical.”
Another recent report warned we are miles off making ‘space babies’ as radiation, microgravity and even toxic lunar dust could scramble fertility, derail pregnancies and endanger future offspring.
Space poses severe challenges to human reproduction. Radiation can damage DNA and increase cancer risk; microgravity disrupts hormones, gamete quality and embryonic development.
It’s not just rays and weightlessness. Hazardous dust, limited resources, contamination in sealed spacecraft, circadian disruption and stress all threaten maternal and foetal health – with potential long‐term, heritable effects.
