Elon Musk’s ever-growing brood of children has expanded once again after he confirmed the arrival of a new son named Seldon Lycurgus.

Shivon Zilis and Elon Musk’s with two of their children. The couple have not yet posted a photograph of their latest addition, Seldon Lycurgus – X

The baby is believed to be his 14th child and the fourth he has had with Shivon Zilis, a Canadian executive at Neuralink, his neurotechnology firm.

The billionaire, now working with Donald Trump as the head of the department of government efficiency or Doge, has forged a reputation for giving his children highly unusual names, including Exa Dark Sideræl, Strider, Azure and X Æ A-12, known as X for short.

Ms Zilis announced the birth on X, the social media platform owned by Mr Musk, and also disclosed the name of their third child, which had been unknown until now.

Shivon Zilis said her son Seldon Lycurgus has a ‘solid heart of gold’ – X

“Discussed with Elon and, in light of beautiful Arcadia’s birthday, we felt it was better to also just share directly about our wonderful and incredible son Seldon Lycurgus,” 38-year-old Ms Zilis wrote.

“Built like a juggernaut, with a solid heart of gold. Love him so much,” she wrote. Mr Musk responded with a heart emoji.

The founder of SpaceX and Tesla believes that humanity is at risk from declining birth rates and has signalled his intention to have a large number of children.

“Bravo to big families,” the 53-year-old billionaire said three years ago. He has described falling birth rates as “the biggest danger civilisation faces by far.”

His offspring have been born to at least three different women: Ms Zilis; the Canadian electropop musician Grimes, whose real name is Claire Boucher; his ex-wife, author Justine Wilson; and, allegedly, with a glamorous young Maga influencer called Ashley St Clair, 26.

Ashley St Clair has filed a lawsuit claiming that Elon Musk is the father of her son – X/Twitter

She has filed a lawsuit claiming that Musk is the father of her five-month-old son.

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Ms St Clair says there is no doubt about the paternity of the baby. In her lawsuit, she insisted that she “did not have sexual intercourse with any other male during the time the child was conceived.”

As part of her evidence, she included text messages allegedly sent to her by Mr Musk. In one exchange, he allegedly wrote: “I look forward to seeing you and him this weekend.”

On X, she wrote: “Five months ago, I welcomed a new baby into the world. Elon Musk is the father.”

Mr Musk has yet to respond publicly to her claim.

At the time that she met Mr Musk, she was working for the conservative satirical website The Babylon Bee, a Christian, Right-wing version of The Onion.

A regular guest on conservative news outlets, she has warned about declining birth rates in developed countries, a concern shared by many Republicans.

Mr Musk has six children with his first wife, followed by three with Grimes and now four with Ms Zilis.