Elon Musk vs. Mark Zuckerberg

Musk, who says he's worried about population collapse, has nine children with three women, including triplets and two sets of twins. As a kid in South Africa, Musk taught himself to code; he sold his first game, Blastar, for about $500.

Zuckerberg and his wife, Priscilla Chan, are spending $3 billion in an attempt to end, cure or manage all disease by the year 2100. In January 2019, Mark Zuckerberg purchased $59 million worth of waterfront property on Lake Tahoe in California.