Some of the biggest names in sports gathered in New York on Tuesday to discuss the importance of youth sports — and the funding gap that is shutting down sports programs across the country.

Twenty-seven percent of U.S. public high schools will have no sports by the year 2020, according to an estimate from the non-profit Up2Us Sports.

“If you think about that, it’s really catastrophic for our kids,” Ed Stack, CEO of retailer Dick’s Sporting Goods told CNBC. His company has pledged more than $50 million to the cause.

Tom Brady, Serena Williams and Missy Franklin were a few of the athletes who talked about how sports shaped their lives for the better.

“To hear that not as many people are participating…it’s very sad to hear that,” said Tom Brady, who added that his earliest memories of sports were watching his sisters on the softball field.

Studies from the Aspen Institute have shown that physically active kids achieve higher test scores and have an 11 percent higher graduation rate than non-athletes.

The number-one tennis player in the world, Serena Williams, said she’s been able to take the success she’s learned on the tennis court and apply it to her life outside of tennis. “Never give up,” she said. “Not everything you start is going to be an instant success.”

Being an athlete has taught 20-year-old, gold-medal-winning swimmer Missy Franklin confidence and self-esteem: “I find that the most important thing is to believe in yourself first and foremost and use that to motivate yourself every day.”