There is seemingly no material exempt from a Twitter punchline for Elon Musk. On Thursday—a day after news broke that he had fathered twins with one of his executives at Neuralink, the brain-implant startup he cofounded—Musk tweeted that he is doing his part “to help the underpopulation crisis.” He added that “a collapsing birth rate is the biggest danger civilization faces by far.” Musk now has nine known children. Earlier this year, the billionaire faced misconduct allegations at another of his companies, SpaceX, after Insider reported that a flight attendant had accused him of propositioning her while flying on a company plane. Musk denied the allegations and also attempted to use them as comedic fodder, tweeting, “Finally, we get to use Elongate as scandal name. It’s kinda perfect.”