How could Michael Jordan, born with once-in-a-generation athletic abilities, soar as one of basketball's greatest players of all time ... only to whiff his chance at a career in Major League Baseball?
Or why has William Shatner with his talent in the performing arts been acting successfully for over four decades in hits like Star Trekand "Boston Legal," but failed to launch a singing career?
In their new book "SuperFreakonomics," authors Steven Levitt and Stephen Dubner propose some answers.
"The fact is, if you look at anybody in the world who's really, really good at anything, the odds are that they were not so great at that when they were a little kid," Dubner said. "This whole idea of raw talent and genius are vastly overrated."
Born to be a great soccer player or a pianist? Not so, says Dubner. Sometimes something as simple as the month you were born can help make it possible for you to succeed.
Watch this story and more "SuperFreakonomics" on "20/20" Friday at 10 p.m. ET
"It's a bizarre, but very pronounced pattern, that if you look at, let's say, world class soccer teams, a lot of the guys on those teams were born in just a few months of the year -- turns out January, February and March. And very few of them are born, like, October, November, December," he said.
Dubner said this is not an astrological anomaly. Aquarians are not better soccer players than Sagittarians. Instead, the pattern exists because the cut-off age for youth soccer is Jan. 1 and being the oldest kid on your junior soccer team -- if only by a few months -- can actually determine your chance of becoming a professional soccer player.
"The older kids are bigger. They're a little more mature. They're a little faster," he said. "And then the coaches are looking for the best players. They select them and they keep doing this over and over, year after year."
"What's remarkable is that this effect, this relative age effect, lasts all the way up into the professional ranks," Dubner said. "That's what's really so astounding about it."
The month you are born can also create devastating obstacles. For example, why should some pregnant women pray their baby is not born next May?
Babies born next May in places as far apart as southeastern Uganda and parts of Michigan, will be roughly 20 percent more likely to develop visual, hearing or learning disabilities than babies born in any other month next year, according to the SuperFreakonomics authors.
"It's a mystery until you figure out that those areas are where there's a very large Muslim population. And -- a lot of -- many Muslims, including a lot of pregnant women, fast during the month of Ramadan," Dubner told 20/20. "And if a pregnant Muslim woman fasts during Ramadan and with [the] first or second month of her pregnancy, there's a real chance that her child could have developmental difficulties."
This year Ramadan was from mid-August to mid-September.
It's an unintended consequence of an unexplored phenomenon.
"If you look at the right data with a different mindset, a new kind of question, you can shed light on -- on fundamental questions that have gone unanswered for thousands of years," said Levitt, the economist of the "SuperFreakonomics" duo.