As humanity grapples with global challenges—from pandemics to climate disasters—some scientists are looking beyond Earth for a solution. Establishing colonies on the Moon or Mars could serve as a safeguard against extinction. However, the ability to reproduce in space remains an unanswered question. Teruhiko Wakayama, a professor at the University of Yamanashi’s Advanced Biotechnology Centre, is leading groundbreaking research using freeze-dried mouse sperm aboard the International Space Station (ISS) to explore mammalian reproduction in space.
The Space Sperm Experiment
Stored in a radiation-protection box on the ISS, the mouse sperm specimens will return to Earth in 2025. Wakayama’s team aims to analyze their viability and determine whether they can produce healthy offspring after prolonged exposure to space conditions. This isn’t his first space reproduction breakthrough; in a previous study, Wakayama demonstrated that mouse sperm stored in space for six years could produce healthy baby mice. His findings suggested that freeze-dried sperm could remain viable for 200 years in space.
Yet, Wakayama believes that’s still insufficient. His latest work focuses on developing a device that protects sperm stored at room temperature from radiation, potentially extending its lifespan indefinitely.
“Our aim is to establish a system for safely preserving Earth’s genetic resources in space—ensuring life can be revived even if Earth faces catastrophic destruction,” Wakayama says.
The Next Step: IVF in Space
While the focus has largely been on species like frogs, fish, and even cockroaches that have reproduced in space, mammals present a more complex challenge. Wakayama is working on a device that will enable astronauts to conduct rodent in vitro fertilization (IVF) aboard the ISS. If successful, the research could open doors to understanding the challenges and solutions for human reproduction in microgravity.
Virginia Wotring, a professor at the International Space University, explains the significance:
“We have seen phases of reproduction occur in space for some species, but mammals are the next natural step. Understanding this is crucial for long-term space habitation.”
Why Space Reproduction Matters
If humans are to become a multi-planet species, reproductive capability is vital. While ambitious programs like NASA’s Artemis mission plan to return astronauts to the Moon by 2026, and SpaceX aims for a crewed mission to Mars in the near future, there’s still much to learn about human survival in space.
Space travel exposes the human body to cosmic radiation, which damages DNA and increases cancer risks. Microgravity further complicates the picture, causing muscle and bone loss, vision problems, and weakened immunity. Wakayama highlights the potential for damaged DNA in sperm and eggs to pass genetic abnormalities to offspring, posing significant risks.
Additionally, the absence of gravity may impact the development of a fertilized embryo. “We don’t know if systems like the nervous system and limb development will occur properly in microgravity,” Wakayama explains.
The Road to Space Colonization
Wakayama’s experiments could answer critical questions for humanity’s future in space, including whether species can procreate and thrive in off-world environments. His work might also pave the way for transporting genetic resources, livestock, and even pets to other planets to sustain space-based communities.
While his focus remains on mice, Wakayama hopes the results will eventually provide insights into human reproduction. “In sci-fi movies, babies are born on other planets, but we don’t know if that’s possible yet,” he says.
A Future Beyond Earth
Humanity’s journey toward space colonization faces many hurdles, but Wakayama’s work could prove pivotal. Whether freeze-dried sperm can withstand space indefinitely or if mammals can develop and reproduce normally in microgravity are questions that must be addressed for survival beyond Earth.
“If we can confirm that reproduction is possible, it will bring reassurance,” Wakayama says. “And if it doesn’t work, we need to understand how to address that challenge.”
By pushing the boundaries of space reproduction research, Wakayama and his team are bringing us closer to answering a fundamental question: Can life truly thrive beyond Earth? If the answer is yes, it could be humanity’s most significant insurance policy for the future.
