The four women who will represent the United States in tennis singles at this year’s Olympics—including Serena and Venus Williams—are all African-American. This is a first for the sport. Photograph by LEON NEAL / AFP / Getty

The news about Olympic tennis, which begins on Saturday, has, so far, mostly concerned those who won’t be playing. Maria Sharapova is out, barred from all tournament play for using the newly banned performance-enhancing drug

The hazy complexity of this process notwithstanding, the resulting U.S. teams, men’s and women’s, offer a crystalline glimpse of the state of American tennis. The four women who will represent the United States in singles—Serena Williams, Venus Williams, Madison Keys, and Sloane Stephens—are all African-American. This is a first for the sport. And that would perhaps seem more surprising, given tennis’s unyielding country-club-confines image, were it not that the Williams sisters have been playing, and winning, for so long now. This is Venus’s fifth Olympics, and Serena’s fourth (she sat out the 2004 Games with a knee injury). They have won a combined five gold medals: one apiece in singles, three as a doubles team. Their staying power, and all that they have accomplished both on and off the court, have inspired other young African-American women, like Keys and Stephens, who are both in their early twenties, are now both Top 25 players, and both play the kind of mighty-shot offense and attacking defense that the Williamses brought to women’s tennis. And there are other young black women coming up in the game: Taylor Townsend, for instance, and the remarkably named teen-age sisters Tornado and Hurricane Black. For these young female athletes, tennis is a big-time sport. That is one of the legacies of Venus and Serena.

The contrast with the men’s game is stark. The only African-American on the A.T.P. tour in recent years has been Donald Young, who has never won a tournament. The U.S. men slated to play singles are all white. None are likely to win a medal. (Don’t count on a U.S. medal in men’s doubles either: the Bryan brothers won a gold in doubles at the London Games in 2012, but withdrew from the Rio Games last weekend, citing Zika. One of their replacements, thirty-two-year-old Rajeev Ram, is the son of Indian immigrants, and the only person of color on the U.S. men’s team.) Two of the top three Americans in the A.T.P. rankings, John Isner and Sam Querrey, chose not to go to Rio. Two of the Americans who will be playing singles, Brian Baker and Denis Kudla, are ranked outside the Top 100. This is a long way from the nineteen-nineties, when American men dominated tennis, and when Andre Agassi—in Atlanta, in 1996—won a gold.

John McEnroe and others have said that, unless tennis begins attracting the best male athletes, the United States is unlikely to produce a champion in men’s singles. If the other major American sports are any indication, a large number of the best male athletes in this country are black, and many of them have grown up in poor neighborhoods. As McEnroe sees it, tennis has not attracted these kids because they can’t afford the costs associated with the lengthy, individual training necessary to become a top pro player. His tennis academy, on Randall’s Island, in New York, is designed, at least in part, to be a magnet for underprivileged youth; there are scholarships available, and you do not need to move to Florida to attend a camp.

But it’s not clear that such an approach, however worthy, will bring about the changes that are needed. It could well be that the problem is not just the cost on the front end but the payoff down the road. The two sports that currently attract most of the best young athletes in America, basketball and football, offer the kind of money that is earned in tennis only by a handful of players at the very top. Thanks to a nine-year TV deal garnered by the N.B.A. two years ago, the salary cap that each team must stay under (more or less) has grown to $94 million; a player who comes off the bench can earn $15 million a year. In 2016, so far, John Isner, America’s top men’s player, has earned $657,000 in prize money.

It’s different for women. Most of the top-earning female athletes in the world, according to Forbes, are tennis players. Serena Williams earned about $29 million this past year, in combined prize and endorsement money, and her net worth is said to be close to $150 million. A top W.N.B.A. player makes a little over $100,000. If you are a woman with the speed, strength, coördination, and desire necessary to be a professional athlete, nothing is more economically promising than a tennis court. But that’s not the case for men—not in the United States. And, unless that changes, the country’s best male athletes will, most likely, continue to play other sports.