Nelly Korda swung her first golf club, the plastic kind, as a toddler. Her statuesque parents, two world-class tennis players, toted her along to older sister Jessica’s practice sessions. Nelly had her first lesson at age 6 and won the first event she ever played, in the Czech Republic, as a 9-year-old – curiously, taking home a bottle of champagne as a prize. Nelly Korda, now 19, still isn’t old enough to drink champagne, but she is already in her second year on the LPGA Tour alongside Jessica, 25, her idol and best friend. 

The Kordas are one of two sets of sisters in the field for the 73rd U.S. Women’s Open, joining Thailand’s Ariya and Moriya Jutanugarn. All four have the game to claim the championship at Shoal Creek. Ariya, the 2016 Ricoh Women’s British Open champ, is a seven-time winner on the LPGA Tour; Jessica has five LPGA titles. Moriya won for the first time in April, and Nelly is due to win any week.

“I don’t think it’s ever not going to be cool,” said Jessica of having a locker next to her sister’s at the Women’s Open.

It’s hard to imagine there are too many families in the world with more athletic talent than the Kordas. Petr Korda and his wife, Regina, have been together for 32 years. They met on the junior tennis circuit at age 9 and turned professional at 18, their career progress slowed because they weren’t allowed to travel freely outside of communist Czechoslovakia until they were ranked higher than 120th. Back then, more than half their earnings went to the government. Jessica, born in Florida, turned pro at age 17 and understood from an early age that she was fortunate.

Petr would win the 1998 Australian Open but he insists that Regina, an Olympian, was the more talented player. At 19, Regina fell in the locker room while stretching and busted her kneecap. Doctors told her she might not walk again, but she eventually climbed into the top 25 in the world more or less on one leg.

While Jessica and Nelly are regularly popping up on LPGA leader boards, younger brother Sebastian, a rising star in tennis, won the boys’ junior title at the Australian Open in January. Sebastian copied his father’s celebratory scissor-kick after the win, as had Jessica when she won the 2012 Australian Women’s Open at Royal Melbourne Golf Club. Still, don’t ask Petr to compare his children to each other, or to their parents. He won’t do it.

“Every child gets DNA from their parents,” said Petr, “but it’s not about talent. It’s how you put it together, what you do with it.”

From the beginning, Petr has preached the merits of balance. Jessica qualified for her first U.S. Women’s Open at age 15 and tied for 19th. But she also spent much of her summer visiting family in the Czech Republic. Petr exposed Jessica to high levels of golf at an early age but kept her tournament schedule light compared to most elite juniors. She was a finalist to Danielle Kang in the 2010 U.S. Women's Amateur and a member of that year’s Curtis Cup Team, partnering with Lexi Thompson en route to victory.

Nelly took it slow, too, taking summers off to hang out by the pool and play soccer. Still, Nelly managed to qualify for her first Women’s Open at age 14, one-upping big sis.

Petr had thought golf too slow but got into the game after listening to Ivan Lendl gush about it in the locker room on the tennis circuit.

“I always felt the sport was when you die, then you can play,” he joked.

Petr never wanted any of his kids to take up tennis. Sebastian started off in hockey. When the girls showed a love for golf, Petr caddied often for them but preferred to stay in the background. When Sebastian made the switch to tennis, Jessica knew he’d have the toughest path of all. To that end, Petr stayed home in Bradenton, Fla., when Sebastian went to Australia on the 20th anniversary of his father’s Grand Slam title. Petr saw the victory from his couch, with the family cat in his lap.

Both Petr and Regina know from experience what their children are feeling on the biggest of stages. They know what to say and when to say it. It’s a gift that’s not lost on Jessica.

“They’re just really proud of us,” she said, “and we’re very fortunate to have parents that aren’t on top of us all the time. That gave us room to grow and make mistakes.”

At one point during the third round of February’s Honda LPGA Thailand, the Kordas and Jutanugarns held the top four spots on the leader board. Of the 10 sets of sisters that have competed on the LPGA Tour, only the Jutanugarns and Annika and Charlotta Sorenstam have each won titles. Charlotta, maybe not coincidentally, was paired with her sister on the day Annika shot the LPGA’s first and only 59.

The Jutanugarns are closer in age than the Kordas and were staples at USGA events together as junior players, taking turns caddieing for each other during match play. The younger and taller Ariya, 22, won the 2011 U.S. Girls’ Junior while Moriya, 23, lost to Kang in the 2011 U.S. Women’s Amateur final three weeks later. The sisters — known as May (Ariya) and Mo — travel together nearly every week with their mother, Apple, who played while pregnant with them both back in Thailand. Mo is the organized perfectionist, down the middle both inside and outside the ropes. May hits it hard on the course but can be found most nights vegging for hours on Thai TV dramas.