Serena Williams fell just shy of another Wimbledon title earlier this month. (Tim Ireland/Associated Press)

In historian Randy Roberts’s inaugural examination of a sports icon, “Papa Jack: Jack Johnson,” on the first black man allowed to fight for the heavyweight boxing championship of the world, Roberts noted one reason black fighters had not been afforded such an opportunity was because they were thought to be innately advantaged by thicker skulls and a lack of sensitivity to pain.

In his most recent sports biography, released in March, “A Season in the Sun: The Rise of Mickey Mantle,” Roberts told me he and co-author Johnny Smith found the opposite.

“No one tried to make a genetic explanation for how Mickey Mantle hit a baseball a mile from both sides of the plate,” Roberts said. “That takes place more with black athletes than with white athletes. There’s always that, ‘How do we explain it?’ ”

The website Deadspin revealed data this month that suggested tennis was trying to explain how Serena Williams is so great, still, even as a new mother in her mid-30s after a dangerous delivery of her baby girl. Deadspin showed that Williams was tested for banned performance-enhancing drugs significantly more often than her competitors.

Williams responded to the report Tuesday on Twitter, where she wondered whether she was a victim of discrimination. “It’s that time of the day to get ‘randomly’ drug tested and only test Serena. Out of all the players it’s been proven I’m the one getting tested the most. Discrimination? I think so,” Williams tweeted.

It is difficult to prove whether Serena has been singled out for any particular reason: her nonpareil excellence, her continued success at an age when most tennis players are done or, most disturbingly, her status as a racial minority in a predominantly white sport. We do know that the U.S. Anti-Doping Agency has tested her five times this year thus far, or more than twice as much as her competitors and more than the top five U.S. men’s players.

We don’t know yet about the International Tennis Federation, which reports only at year’s end and only provides ranges for how many times it tested any athlete, but a recent ESPN.com report suggested the ITF didn’t test Williams disproportionately more than others. We don’t know yet about the World Anti-Doping Agency, which can test any athlete in any sport at any time.

No matter, it is fully understandable that Williams would react to the allusion of the data as aspersion against her accomplishments. There is a long lineage of black athletes, going back at least to Johnson, whose excellence has somehow been met quite publicly by suspicion.

“This crops up from time to time,” said Damion Thomas, the curator of sports at the National Museum of African American History and Culture. “Suspicions about whether African American athletes are cheating or have some sort of genetic advantage or superiority somehow tied to slavery.”

To be sure, Jimmy “the Greek” Snyder, sitting in D.C.’s now-defunct famous eatery Duke Zeibert’s back in January 1988, infamously ascribed the talents of black NFL stars to breeding in the antebellum South. He lost his analyst job predicting NFL games on CBS shortly after.

Any number of newspaper stories, academic journal articles and books, such as Jon Entine’s “Taboo: Why Black Athletes Dominate Sports and Why We’re Afraid to Talk About It,” have been published arguing that black athletes’ success may be a product of genetics rather than diligence and, most disconcerting, intelligence.

“There’s an insidious quality to it,” Roberts said. “They’re saying [black athletes are] better because . . . they’re not like us.”

Ghanaian American Freddy Adu’s prodigious talent as a teenage soccer player in the early 2000s generated loud rumors that he couldn’t be 14 years old.

Tiger Woods stood out on the golf course because of his black and Thai heritage, winning 12 majors in nine years, and a physique highlighted by a red shirt on Sundays led some to whisper he was on steroids or HGH. A book published in 2014 linked Woods to a Canadian doctor busted at the U.S. border for smuggling HGH, though no proof of Woods receiving PEDs was compiled.

Former longtime NBA coach George Karl stated unequivocally in his 2017 memoir, “Furious George: My Forty Years Surviving NBA Divas, Clueless GMs, and Poor Shot Selection,” that NBA players were juicing — taking direct shots, it seemed, at Kobe Bryant, who sought medical treatment in Germany, and even LeBron James, whose physique has generated rumors of PED use.

“It’s obvious some of our players are doping,” Karl wrote. “How are some guys getting older — yet thinner and fitter? How are they recovering from injuries so fast? Why the hell are they going to Germany in the offseason? I doubt it’s for the sauerkraut.”

“One of the things that hasn’t trickled down to the public,” Thomas said, “is the training regimen [of athletes]. It’s so different than what it used to be.”

Thomas noted proactive procedures, most notably Tommy John surgery for baseball pitchers, in some cases in their teens.

“Part of the issue with Serena — and Venus — is so many things they did are outside the orthodoxy of the game,” he said. “They get otherized because of that.”

Of course, there have been standout black athletes who have proved to be pharmaceutical cheats, just like Lance Armstrong or Mark McGwire. Most infamously, they are slugger Barry Bonds and sprinter Ben Johnson.

But Serena’s sin?

“She’s . . . just better than anyone,” Roberts said. “She is what she is.”

Kevin B. Blackistone, ESPN panelist and visiting professor at the Philip Merrill College of Journalism at the University of Maryland, writes sports commentary for The Washington Post.