As humanity faces existential threats such as pandemics, climate change, and natural disasters, the concept of becoming a multi-planetary species is gaining momentum. Proponents of space colonization argue that establishing outposts on the moon or Mars could act as an insurance policy against global catastrophes. However, fundamental questions remain unanswered—chief among them is whether humans can reproduce and thrive in space.
Groundbreaking experiments involving freeze-dried mouse sperm aboard the International Space Station (ISS) could bring us closer to answering this question. Teruhiko Wakayama, a leading reproductive scientist from Japan’s University of Yamanashi, is spearheading research that could illuminate the feasibility of mammalian reproduction off Earth.
Mouse Sperm in Space: A Step Toward Reproductive Research Beyond Earth
Freeze-dried mouse sperm, carefully stored aboard the ISS in a radiation-shielded box, is part of Wakayama’s mission to determine the impact of the space environment on reproduction. Upon its return to Earth in 2025, the sperm will undergo rigorous testing to evaluate its viability for creating healthy offspring.
Wakayama, who developed the first cloned mouse in 1997, has already demonstrated the viability of space-preserved sperm. A previous study involved freeze-dried mouse sperm stored aboard the ISS for up to six years. Once rehydrated, the sperm produced healthy baby mice, leading researchers to conclude that such samples could remain viable for up to 200 years in space.
However, Wakayama acknowledges that 200 years is insufficient for long-term space missions or interstellar preservation. His latest experiment involves using advanced devices to protect sperm stored at room temperature from cosmic radiation, potentially extending viability indefinitely.
“Our aim is to establish a system for safely and permanently preserving Earth’s genetic resources somewhere in space, whether on the moon or elsewhere,” he explains. This would ensure life could be revived even if Earth experienced catastrophic destruction.
From “Chix in Space” to Cosmic Cockroaches: Reproduction Research in Space
For decades, scientists have studied how microgravity and cosmic radiation affect biological processes, including reproduction. Some notable milestones include:
- 1989: Fertilized chicken eggs were sent to orbit in an experiment whimsically called “Chix in Space.”
- 1992: Tadpoles hatched aboard the Space Shuttle Endeavour swam erratically in microgravity, struggling to locate air bubbles.
- 2007: A cockroach named Nadezhda gave birth to 33 offspring conceived in orbit. While mostly normal, the babies had unusually dark exoskeletons.
Virginia Wotring, a professor at the International Space University in France, notes that reproduction in simpler organisms like amphibians, fish, and snails has been partially successful in space. Moving to mammals, however, presents unique challenges due to their complex development processes.
Challenges in Space Reproduction
Despite successes with rodents, humans face additional hurdles for reproduction in space. Cosmic radiation, for example, could damage DNA in sperm and eggs, increasing the risk of genetic abnormalities in offspring. Without gravity, embryonic development could also be affected, particularly in forming the nervous system and limbs.
“The formation of the nervous system and the development of limbs … we don’t know if this will happen properly in microgravity, where there is no up or down,” Wakayama cautions.
Wakayama’s ongoing work aims to address these challenges, paving the way for future research on other species, such as livestock for food and dogs for companionship. His team is also developing a device that would allow astronauts to conduct in vitro fertilization (IVF) experiments aboard the ISS. This project, accepted by Japan’s space agency, could launch within two years.
Implications for Space Colonization
As space programs like NASA’s Artemis mission and SpaceX’s Mars initiatives advance, understanding reproduction in space becomes increasingly important. Sustaining human populations on other planets will require the ability to reproduce and maintain genetic diversity.
However, Wotring emphasizes that current priorities should focus on the immediate health challenges faced by astronauts, including cosmic radiation and microgravity-induced bone loss. “There is other information that we need right now to care for the astronauts we’re sending to space,” she says.
Still, Wakayama believes his work could be transformative for long-term space exploration. By ensuring that humans and other species can reproduce and develop normally in space, his research offers hope for a future beyond Earth.
A Sci-Fi Future Turning into Reality?
Wakayama’s experiments challenge the boundaries of what’s possible in space. “In sci-fi movies, people live on other planets and babies are born, but we don’t even know if that’s possible yet,” he reflects.
His ongoing research, from cloning mice to preserving genetic material in space, represents a crucial step toward addressing these unknowns. “If we can confirm that reproduction works in space, it will bring reassurance,” Wakayama says. “And if it doesn’t, we need to understand how to address that challenge.”
As humanity prepares for life beyond Earth, experiments like these are not just scientific curiosities—they are vital blueprints for our survival as a species. Could freeze-dried mouse sperm orbiting Earth be the key to unlocking humanity’s future? Only time—and science—will tell.
