Elon Musk fathered two children in 2021 with Shivon Zilis, a top executive at his artificial intelligence company Neuralink, new court documents show.The world’s wealthiest man now has nine known children, including five children with his first wife, Justine Musk, and two with the singer Claire Boucher, known professionally as Grimes.Court documents obtained by Insider and published on Wednesday showed that Elon Musk and Zilis filed a petition to change their twin babies’ names to “have their father’s last name and contain their mother’s last name as part of their middle name”.The petition was filed in Austin, Texas, where the babies were born, and was approved by the judge. Zilis reportedly gave birth in November 2021, weeks before Musk and Boucher had their second child via a surrogate.Zilis, 36, was born in Canada and studied economics and philosophy at Yale before working at IBM and later at Bloomberg Beta, a venture capital fund. She is considered a rising star in the world of artificial intelligence and has been listed on Forbes’ 30 Under 30 in and LinkedIn’s 35 Under 35.According to her LinkedIn, Zilis works as director of operations and special projects at Neuralink, Musk’s neurotechnology firm, which seeks to create human-machine interfaces. She began working at the company in May 2017.In 2022, animal rights organizations filed a complaint with the US Department of Agriculture over animal abuse charges related to the monkeys used in Neuralink experiments. Neuralink called the claims “misleading”.Musk helms several companies including Neuralink, the electric car company Tesla, the space travel company SpaceX, and the tunnel construction firm the Boring Company. He recently agreed to buy Twitter for $44bn, a purchase that he has stalled over concerns about bots on the platform. According to Insider, Zilis has “been floated” to run the social media site should the deal go through.Musk in the past has promoted increasing the birth rate, saying “civilization is going to crumble” if people don’t have more children. “I mean, I’m doing my part haha,” he recently wrote on Twitter regarding the declining US birth rate.In April, one of his daughters filed to change her last name and be legally disassociated from Musk, saying she did not want “to be related to my biological father in any way, shape or form”.