Sex in Space: The Final Frontier for Mars Colonization?

future mars settlers
Artist's illustration of colonists on Mars. Scientists don't yet know how babies would develop and grow away from Earth, and this lack of knowledge poses a possible hurdle to establishing sustainable space settlements, experts say. (Image credit: Illustration: Pat Rawlings/NASA)

If humanity is serious about colonizing Mars, we need to get busy studying how to get busy in space.

We just don't know enough about how human reproduction and development work in the final frontier to confidently plan out permanent, sustainable settlements on the Red Planet or anywhere else away from Earth, said Kris Lehnhardt, an assistant professor in the department of emergency medicine at The George Washington University School of Medicine and Health Sciences.

"This is something that we, frankly, have never studied dramatically, because it's not been relevant to date," Lehnhardt said May 16 during a panel discussion at "On the Launchpad: Return to Deep Space," a webcast event in Washington, D.C., organized by The Atlantic magazine. [The Human Body in Space: 6 Weird Facts]

"But if we want to become a spacefaring species and we want to live in space permanently, this is a crucial issue that we have to address that just has not been fully studied yet," he added.

Off-Earth reproduction isn't a completely ignored topic, of course. Just last month, for example, a group of researchers in Japan announced that freeze-dried mouse sperm that was stored on the International Space Station for nine months gave rise to healthy pups.

Those results suggest that the relatively high levels of radiation experienced in space don't pose an insurmountable barrier to reproduction.

But the mouse sperm was brought back to Earth to produce embryos, which grew here on terra firma. How a human embryo would fare when away from Earth — in the microgravity environment of orbit or deep space, or on Mars, whose surface gravity is just 38 percent as strong as that of our planet — remains a mystery, Lehnhardt said.

"We have no idea how they're going to develop," he said. "Will they develop bones the way that we do? Will they ever be capable of coming to Earth and actually standing up?"

And there's a lot to think about beyond the nuts-and-bolts developmental issues. For example, people who are born and grow up on Mars, or in huge Earth-orbiting space habitats, "are going to be vastly different from what we are," Lehnhardt added. "And that may be kind of a turning point in human history."

The panel discussion also featured former NASA astronaut Michael López-Alegría; Sheyna Gifford, a member of the HI-SEAS IV simulated Mars mission in Hawaii; and journalist Alison Stewart. You can watch the entire discussion on the AtlanticLIVE YouTube channel.

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Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.