Here’s an idea that one of five young South African cousins threw out sometime in the 1980s: What if they could arbitrage the cost of chocolate in an Easter egg? Plain old chocolate at the time cost virtually nothing, but a nicely packaged chocolate Easter egg cost about one rand. So the young cousins melted regular chocolate, molded it into egg shapes, wrapped the chocolate eggs in foil, and went around the poshest parts of their Pretoria neighborhood. And instead of selling these chocolate eggs for the going rate, they cranked up the price to 10 rand.

When neighbors balked at the price, the boys responded as they’d rehearsed. Purchasing from them, they said, would mean the buyer was supporting young capitalists. It worked.

This is not the kind of scheme most 14- or 15-year-old relatives dream up, but these were not most 14- or 15-year-olds. This is a piece of lore essential to understanding what may be the 21st century’s First Family of entrepreneurship, a family of happy capitalists intent on cracking today’s toughest problems by building businesses. Those budding teen tycoons included two sets of brothers: Elon Musk, whom you’ve likely heard of, and his brother, Kimbal, a fellow entrepreneur focused on trying to change America’s food culture; and Lyndon and Peter Rive, the founders of SolarCity. (Their brother Russ now runs the art, technology, and design company SuperUber, in Brazil.) Each family also has a sister: Tosca Musk, a filmmaker, and Almeda Rive, a competitive dirt-bike rider.

Elon may be the most famous of the clan, thanks to his mad-scientist ways and the Beatles-esque buzz surrounding the companies he’s dreamed up—from PayPal to electric carmaker Tesla Motors to aerospace manufacturer SpaceX to what remains—for now—the mere concept of the high-speed Hyperloop. But each of the Musk-Rive cousins has achieved notable levels of success. Kimbal Musk co-founded The Kitchen, a group of eight restaurants that source directly from local farmers, and The Kitchen Community, a nonprofit that’s opened more than 250 school and community gardens that impact 140,000 kids each day. Lyndon and Peter Rive founded SolarCity, the energy-service company that has a market cap of about $4 billion, after Lyndon, Peter, and Russ sold their company, Everdream, to Dell in 2007.

America loves a familial power block—from the Emanuel brothers to the Williams sisters, the Kennedys to the Hemsworths. But there’s something even more intriguing about those Musks and Rives, given what appears to be their genetically pre-programmed ambition. How did five of them grow up to take on some of the knottiest problems on the planet, setting goals so lofty as putting civilians in space and transforming household energy use?

This being an origin story, it all has a great deal to do with their mothers: Maye and Kaye. They are—what else?—twins.

Maye, who was divorced from Elon and Kimbal’s father before Elon was 10, has two master of science degrees, practiced as a dietician, and worked on the side as a model to pay bills as a single mother.

“They grow up knowing you work hard, and the harder you work, the better you do and the luckier you get,” she recently told VF.com. “They also had to be responsible for themselves, because they had to help me.”

Lyndon Rive, whose parents were entrepreneurs in the natural-health business, recently recalled watching his mother—Kaye—work from 7 in the morning until 11 o’clock at night, every day.

“We grew up thinking that’s what people do, isn’t it? That’s what’s expected,” he says.

This bred quite a bit of independence, and quite a bit of time for the cousins to get up to something. The fact that they didn’t get allowances meant they spent that free time trying to come up with ways to make a buck. That they grew up 20 minutes away from each other made it easy to scheme together.