Elon Musk has reportedly offered his sperm to help colonize Mars. It's unclear if that's possible.

• Elon Musk offered his sperm to seed a settlement on Mars, anonymous sources told The New York Times.
• Secretive teams at SpaceX are investigating options for a Mars colony, including reproduction, according to the report.
• It's unclear whether it's possible to have babies on Mars due to high radiation and low gravity.

Elon Musk's obsession with Mars has reached new heights.

The billionaire SpaceX CEO is so enamored with his vision of starting a colony on the red planet that he's offered to donate his sperm to the cause, according to a report The New York Times published on Thursday.

According to the report, which is based on over 20 interviews the NYT conducted and internal SpaceX documents, Musk has quietly directed SpaceX employees to investigate the details of how a Mars colony would work, with one team focusing on dome habitats, another team on spacesuits, and another on reproduction. Two anonymous sources told the Times that Musk had volunteered his sperm.

Musk has long touted a thriving Mars settlement as his life's top ambition, saying it's necessary to make the human species interplanetary in case of an extinction event like an asteroid impact.

But Musk has also been waging a personal battle against his fears of underpopulation — which he has called "the biggest danger civilization faces" — by fathering a lot of children.

He has had 12 known children with three different women, including with Shivon Zilis, one of his top executives.

It's only fitting that Musk might take that mission to Mars. However, it's not yet clear whether human reproduction is possible on the red planet.

Making babies in space

"Studies have shown that you can send freeze-dried sperm into space sealed, like freeze-dried coffee effectively," Adam Watkins, associate professor of reproductive biology at the University of Nottingham, previously told Business Insider.

"You would then do something like IVF with those sperm and eggs and transfer the embryos into females who are already established at the other end," such as in a Mars settlement, he explained.

At that point, though, things get complicated and risky. Being in space, with reduced gravity and lots of radiation, is tough on the human body.

"We don't even know if it's possible for someone to become pregnant in space," Dr. Kris Lehnhardt, who leads research at NASA on medical systems for deep-space exploration, previously told BI.

Even if a person could become pregnant beyond Earth, the intense radiation in space could be harmful to a developing embryo or fetus. Mars offers little protection from solar and cosmic rays. It's atmosphere is just 1% the volume of Earth's.

Musk has previously indicated that giant glass domes and possibly even living underground could help protect Mars residents from harmful radiation, but by how much is unclear.

A person standing on the surface of Mars would also experience only 38% of the gravity on Earth. It's uncertain how that would affect a pregnancy.

Musk isn't the only one trying to figure this out. A company called SpaceBorn United is researching the feasibility of in vitro fertilization (IVF) in space, planning to try space IVF on mouse embryos. Eventually, the initiative aims to test on human embryos.

"When you look at what will be needed for us to be an off-planet species, that starts to stick out as one of the really, really big unknowns," David Cullen, a professor of space biotechnology at Cranfield University who is working with SpaceBorn United, previously told BI.

Musk and SpaceX did not respond to a request for comment.