San Francisco, Jul 8 (IANS): Tech billionaire Elon Musk has shown his support for large families a day after court documents revealed the tech billionaire had twins with a senior executive at one of his companies.

On the microblogging platform Twitter, Musk also wrote that the "population of Mars is still zero people".

"Doing my best to help the underpopulation crisis. A collapsing birth rate is the biggest danger civilization faces by far," the Tesla CEO wrote on Twitter.

"I hope you have big families and congrats to those who already do," he added.

This week, a report said that Musk secretly had twins with Shivon Zilis, a top executive at his brain-chip startup Neuralink, in November 2021, just weeks before he welcomed a second child with his former girlfriend Grimes via surrogacy in December.

With the newly reported twins, the 51-year-old Tesla CEO now has nine known children.

According to the court documents, Musk and Zilis filed a petition in April to change the twins' names to "have their father's last name and contain their mother's last name as part of their middle name", the Daily Mail reported citing Insider.

Meanwhile, another report said that SpaceX paid $250,000 to a flight attendant who accused Musk of sexual misconduct.

The alleged victim accused Musk of rubbing her leg without consent and offering to buy her a horse in exchange for an erotic massage.