A learning curve this steep is always going to cause suspicion. A South African teen named Caster Semenya outran her competition in the women's 800 meters at the world championships on Wednesday by more than two seconds. Her time of 1 minute, 55.45 seconds clipped more than a second off the 1:56.72 she ran just three weeks ago to win the African Junior Championships - which was more than eight seconds faster than the 2:04.23 Semenya ran last October to win the 2008 Commonwealth Youth Games.
But the cloud hovering over those performances has nothing to do with performance-enhancing drugs - at least not yet. It's about whether the 18-year-old should be allowed to compete against women.
It's too early to say whether Semenya's story is one that's too good to be true. Track and field's governing body will weigh in with a decision on that soon enough. The shame is that it's been dirtied up already.
In the days following what should have been her grand achievement, Semenya has been humiliated and kept under wraps. Her family and countrymen are outraged. Her competitors aren't certain what to think.
"If none of it's true, I feel very sorry for her," said Jennifer Meadows of Britain, who took bronze in the 800 meters.
But a moment later, Meadows added, "Nobody else in the world can do that sort of time at the moment. She obviously took the race by storm."
Semenya's tale begins with a tomboy who always wore pants to school, didn't mind playing rough, and endured plenty of taunts from the boys she regularly competed against in a poor village 300 miles north of Johannesburg. The head of her secondary school thought Semenya was a boy until Grade 11.
What no one doubted is that once Semenya got serious about running, right about the time she entered college, she was eye-popping fast.
"If you go to the athletics track, you're sure to find her there," said Morris Gilbert, a media consultant for TuksSport, the University of Pretoria's sports department. "I don't think she had really good training before she came to the university."
But devotion, hard work and good training, even if it's coupled with the onset of athletic maturity, almost never produce results this fast. Semenya's times so unnerved her competitors that some looked at her muscular build and listened to her deep voice and concluded she wasn't a woman at all.
"They're judging her based on what?" asked South African athletics federation president Leonard Chuene. "Who can give me conclusive evidence? I want someone to do that."
Therein lies the problem.
Any scientist who's studied gender issues can tell you biology doesn't always play by its own rules. The International Olympic Committee dropped mandatory gender exams before the Sydney Games because the standard in place before then - chromosome testing - could be interpreted several ways. In place now is a case-by-case analysis that brings together a gynecologist, endocrinologist, psychologist, an internal medicine specialist and gender expert.
But the IAAF, track and field's governing body, in full accord with IOC policy, will decide Semenya's case according to whether her "conditions ... accord no advantage over other females."
What the rule suggests is that a panel of experts will consider everything from Semenya's genetic markers to her genitalia and then try to decide whether her times fit the profile of the world's fastest woman at 800 meters. It's an educated hunch at best, but at the moment, it's all they have.
IAAF general secretary Pierre Weiss went out of his way to say that testing was ordered because of "ambiguity, not because we believe she is cheating."
But that didn't pacify Semenya's national federation, nor the family that raised her as a girl all her life.
"She is a woman and I can repeat that a million times," her father, Jacob, told the Sowetan newspaper.
"It is God who made her look that way," said Semenya's grandmother, Maputhi Sekgala, who helped raise her.
The IAAF usually initiates gender testing after hearing suspicions from competitors, but the investigations are supposed to be carried out in private. Leaks have already made the process more humiliating than it needed to be. So maybe the only thing we know so far is that the grown-ups in charge could have handled this better.
Jim Litke is a national sports columnist for The Associated Press. Write to him at firstname.lastname@example.org