‘Cosmic child’ seems distant as human sperm show 50% navigation decline in space test

Scientists have carried out an unusual test to determine whether a child could be conceived in space.

The researchers used a tiny plastic “obstacle course” to test how space conditions affect the navigation capabilities of individual sperm cells.

Their tests showed that some sperm cells did make it through, suggesting children may one day be conceived in space. However, the scientists stated that embryo development could still pose a problem.

Studying sperm in space-like conditions

Next week, NASA’s Artemis II mission aims to send humans to the Moon for the first time since 1972. Under NASA chief Jared Isaacman’s new plan, the Artemis program will have a renewed focus on building settlements on the Moon, with a view to eventually colonizing Mars.

All of this poses the question: Will humans be able to reproduce in space? While the new research was focused on microgravity conditions, hypothetical Mars inhabitants will experience roughly 38 percent of Earth’s gravity.

“As we progress toward becoming a spacefaring or multi-planetary species, understanding how microgravity affects the earliest stages of reproduction is critical,” associate professor John Culton, Director of the Andy Thomas Centre for Space Resources, explained in a press statement.

For their study, the researchers tested both human and mouse sperm. To do so, they used a 3D clinostat machine, developed by Dr. Giles Kirby at Firefly Biotech. The machine was designed to resemble the female reproductive tract, and it serves as a “miniature obstacle course”, according to the researchers. The team published their findings in the journal Communications Biology.

“Think of it as a tiny racetrack … sperm are introduced at one end and have to swim their way through to the other,” the scientists told the South China Morning Post (SCMP) in an interview. The machine itself was placed inside a device that uses constant rotation to simulate microgravity.

Space reproduction

The team’s experiments showed that sperm were roughly 50 percent worse at navigating the course under space-like conditions. Interestingly, though, this resulted in roughly a 30 percent drop in fertilization. What’s more, the successful sperm seemed to produce better-quality embryos, which could turn out to be “beneficial”, according to the scientists.

Effectively, the study showed that reproduction in space would only allow the very fittest sperm to survive, in an interesting application of Darwinian evolution.

The results show that reproduction could pose a real challenge for future space settlers, but it still can’t be ruled out as impossible. However, embryo development is where real problems could arise, and more research is required.

Overall, the study shows that microgravity “may not be the deal-breaker we feared, but protecting the embryo from weightlessness in those critical first hours will likely be essential for reproduction in space”, Nicole McPherson, a researcher at Adelaide University in Australia, told the SCMP. While we are unlikely to see the first space baby any time soon, a cosmic child may well be in our collective future.