Elon Musk has denied that he offered up his sperm to help start a colony on Mars.
The SpaceX founder, who has previously warned that humanity must colonize Mars if it is to survive, said he had not made a personal contribution to that effort after The New York Times reported he had volunteered his sperm as part of SpaceX's plans to build a city on the red planet.
"I have not, for what it's worth, 'volunteered my sperm'" wrote Musk in a post on X.
"No one at SpaceX has been directed to work on a Mars city. When people have asked to do so, I've said we need to focus on getting there first," the billionaire added.
According to the NYT report, which is based on interviews with more than 20 people close to Musk and SpaceX and on internal SpaceX documents, Musk has directed SpaceX employees to investigate the details of how a Mars colony would work, with one team drawing up plans for a series of dome-shaped habitats on the red planet. A SpaceX medical team is also reportedly looking into whether it is possible for humans to have children on Mars, the Times wrote.
Two people with knowledge of Musk's comments also told the NYT the Tesla CEO had volunteered his sperm to help grow the colony.
Musk has long been fascinated with Mars. The billionaire founded SpaceX in 2002 with the express goal of reaching Mars, and has spoken extensively about using SpaceX's powerful Starship rocket to travel to Mars.
Experts told Business Insider that it is unclear how practical it would be for Musk to send sperm to Mars.
Adam Watkins, an associate professor of reproductive biology at the University of Nottingham, said that the sperm could be effectively freeze-dried to transport it through space, but other experts have cast doubt over whether it would be possible to become pregnant on Mars thanks to the reduced gravity and high levels of radiation.
Elon Musk and SpaceX did not immediately respond to a request for comment from Business Insider, made outside normal working hours.
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