The past few years have been extremely difficult for planet Earth, with a pandemic leading to unprecedented lockdowns, extreme weather events and natural disasters. All of this has made many people wonder if it is time for humans to find a new place to live, even mentioning the moon or Mars.

There is, however, much we don’t know about our ability to survive and thrive in space—including whether we can reproduce. According to CNN, scientists now hope that frozen mouse sperm, stored on the International Space Station (ISS) in a radiation-protected box, could help better understand the mammals’ ability to reproduce outside of Earth.

Fertilization of rodents in space

When the samples return to earth next year, Teruhiko Wakayama, a professor at Yamanashi University’s Center for Advanced Biotechnology, will study them to determine the impact of the space environment and whether they can be used to create healthy offspring.

Back in his lab in Japan, Wakayama is developing a device that will allow astronauts to conduct rodent in vitro fertilization (IVF) on the International Space Station (ISS) in the coming years. In fact, the experiments could help save humanity, he says.

“Our goal is to create a system for the safe and permanent preservation of Earth’s genetic resources somewhere in space – whether on the moon or elsewhere – so that life can be revived even if Earth faces a total catastrophe,” he says in CNN.

According to the CNN report, it may sound like something out of a science fiction movie, but Wakayama has long pushed the boundaries with his reproductive studies. In 1997, he and another academic developed a new method that they used to clone the world’s first mouse from adult cells.

He led a study on developing mouse embryos in space – something that had previously only been done with creatures such as amphibians and fish. And he and his team pioneered a freeze-drying method used to send mouse sperm to the International Space Station (ISS), where it was stored in a freezer for up to six years. In fact, when the samples were returned to Earth, the researchers were able to create healthy mice.

From this study, they determined that freeze-dried sperm could remain viable for 200 years in space. While this is impressive, Wakayama says that “not enough for our future at all”. With his latest space samples, he uses a new device to protect sperm stored at room temperature from radiation and see if it is possible to store the samples in space indefinitely.

From ‘Chix in Space’ to cockroaches

For decades, scientists have launched Earth creatures into space to study how microgravity and cosmic radiation affect biological processes—including reproduction.

In 1989, for example, 32 fertilized chicken eggs were sent into orbit to study how they would develop without gravity, in an experiment sponsored by the American fast food chain KFC and nicknamed “Chix in Space”.

Cubs born aboard the Space Shuttle Endeavor in 1992 became the first vertebrates to spend their first days in space.

And in 2007, a cockroach named Nadezhda (meaning Hope in Russian) gave birth to 33 offspring captured in orbit. Everything was mostly normal, except for the unusually dark exoskeletons.

“We’ve seen that most of the specific phases of the reproductive cycle can happen in space, at least in one or two species, not always with complete success,” said Virginia Wotring, a professor at the International Space University, a private nonprofit institution.

Genetic abnormalities

In late 2026, the NASA-led Artemis program will send astronauts to the Moon for the first time since 1972, where it hopes to develop a continuous presence. And if SpaceX founder Elon Musk’s predictions are accurate, the first manned mission to Mars could be on its way within the next four years.

Scientists already know that space travel can wreak havoc on the human body. Cosmic radiation can cause DNA mutations that increase the risk of cancer and other diseases. Microgravity can cause vision problems, a weakened immune system, and muscle and bone loss.

That means there are more immediate concerns than reproduction, Wotring says. “There’s other information we need right now to take care of the astronauts we’re sending into space now,” he notes, adding, “That has to be a priority.”

However, Wakayama believes his work will be vital as humans spend more time in space. Damaged DNA in sperm and eggs, for example, could transmit genetic abnormalities to the next generation, he says.

And without the directional pull of gravity, a fertilized embryo may not be able to develop properly.

“In science fiction movies, people live on other planets and have babies, but we don’t even know if that’s even possible,” he says.

He hopes his experiments will help shed light on whether humans can reproduce and develop normally in the harsh environment of space.

“If we can confirm this, it will reassure us,” says the scientist. “And if it doesn’t work out, we have to figure out how to meet that challenge.”