The son of Lindsay Gaze, an Olympic basketballer and coach, Andrew was bred to be a champion. Or so you would think.

Gaze snr was the general manager of the Victorian Basketball Association and one of his jobs was to manage Albert Park Basketball Stadium, a complex in Melbourne with nine courts.

By chance, the stadium had a manager's residence. ''From the time I was born to the day I was 14 I did not have a day where I was not on a basketball court because of where I lived,'' Gaze jnr says.

''On a daily basis you're shooting hoops.''

When Liz Cambage, a star at the Olympics with the first women's slam dunk and a WNBA No.2 draft pick, first played basketball she was ''so unco I hated it''. Even Lauren Jackson, whose parents both represented Australia in the sport, says her support network was more important to her career than any genetic gift.

The question of whether champions are born or made is examined in the book Bounce: How Champions Are Made, written by former British table tennis champion and journalist Matthew Syed.

He debunks the perception of sport being a meritocracy, instead arguing that any sportsperson who has ever won anything of note has benefited from a series of unusual circumstances - including himself.

It's a view shared by several notable former champions and coaches, including Greg Chappell and Denis Cotterell, the man who trained Grant Hackett.

Syed's unusual circumstances were this: his parents bought a tournament-specification table when he was eight; he had a brother who shared his passion for the game, which enabled the pair to play for hours at at a time; a teacher at his school, Peter Charters, was a top national coach; and he and other talented locals had 24-hour access to their suburban club, Omega.

Through a chain of random events, Syed and many of his neighbours were able to train for longer than most children their age and against high-quality hand-picked talent.

Without those advantages, ''I might not even have been No.1001 in England'', Syed says.

Syed's thousands of hours of practice at an early age is significant. There is a theory, first tested by the psychologist K. Anders Ericsson in the 1990s, that says any person who has reached the peak of their chosen profession is likely to have had 10,000 hours' practice.

Ericsson's theory was based on a study of students at Berlin's elite Academy of Music, which found that the major distinction between the stars, those judged to be merely good, and pupils who were bound for teaching careers was the amount of practice they had put in.

The future teachers had clocked just over 4000 hours by the age of 20, the good students had 8000 while the elite had amassed 10,000.

Gaze says he would have passed the five-figure mark very early.

''Every day in some form you're shooting the ball, you've got a ball in your hands, you're playing, doing those type of things, it was a unique environment because of where I lived,'' Gaze says. ''I'm 100 per cent convinced that if I didn't have that environment I don't have the opportunities that come my way.''

Hackett had already clocked 10,000 hours in the pool when he was 16 or 17, Cotterell says. The swimmer claimed the first of his 13 Olympic or world titles soon after, in Perth in 1998.

''He'd been swimming since he was six,'' Cotterell says. ''It's [the 10,000-hour rule] a fair reference, you really do have to put that in.''

Hackett had a ''natural affinity'' with the water but Cotterell says he's never had a pupil as dedicated.

''He could take the hard work, he wanted to do the hard work, he thrived on it,'' Cotterell says.

''He embraced what I gave him but he was demonic about his application to work. He wanted to succeed.''

Hackett's story also bears some similarity to Syed's. Like many Queenslanders, Hackett loved the water - a hobby suited by the state's climate. He had a brother, Craig, who became a champion ironman, whom he could aspire to. He was also part of a strong swimming club where Olympians Daniel Kowalski and Andrew Baildon underlined the value of hard work.

And there was also the Sliding Doors moment - an ironman race where Hackett had gapped the field only to be overhauled by a competitor carried by a well-timed wave.

''He got beaten one year after leading by about 100 metres and someone got a wave and [he] thought that's a stupid sport,'' Cotterell says.

''He's done the work and he wanted to be rewarded for it.

''Swimming's a lonely sport, it's not a team sport, you can't escape. You're standing on the block and you've brought yourself to a level through hard work. There's no lucky days, no lucky breaks.''

Luck, however, does play a part in other sports - right from the bounce of the ball to one's birth date.

Canadian psychologist Roger Barnsley was thumbing through a match program at a junior ice hockey league game when he discovered a remarkable trend in birth dates, which ultimately led to the founding of the relative age theory.

Barnsley noted the disproportionate number of players born in January, February and March and found it was a pattern in every competition, ranging from juniors right up to the National Hockey League.

The explanation was simple. In Canada, the eligibility cut-off date for underage hockey was January 1, and those born earlier in the year were at an advantage.

It's an issue that the AFL's national talent manager Kevin Sheehan says club recruiters have been aware of for years. ''They [players] get into squads and get better coaching and they play in the rep team so they're exposed to higher-level competition as a natural consequence,'' Sheehan says.

''Those boys are given more opportunities and develop quicker. We have to be conscious as recruiters to look through to the bottom age birth.''

Sheehan says the breakdown of players in the AFL was around 52 per cent to 48 favouring those born in the first six months of the AFL's cut-off cycle.

''It's so prevalent in so many other sports,'' Sheehan says.

Cricket is not entirely immune to this phenomena. The cut-off date for underage cricket in Australia is August 31.

Of the 141 players handed a Cricket Australia or state contract for the coming season, 42 players, or nearly 30 per cent, were born in September, October or November.

That's more than any other quarterly period in the cycle though there were more born from June until the end of August (37, 26 per cent) than from December to the end of February (33 players or 23 per cent) or March to the end of May (29 players or 21 per cent).

CA's national talent manager Greg Chappell says relative age theory was not a factor in talent identification but acknowledges how those born earlier in the cycle could be advantaged.

Few sports, however, are at more risk of favouring a particular physical trait than basketball, but Gaze says size is not the only factor to gauging the likelihood of future success in the game.

Shane Heal, a 182-centimetre point guard who had stints in the NBA and was a four-time Olympian, and Derrick Rose, voted the NBA's most valuable player two seasons ago, are two such examples. ''[But] if you've got two guys who can do exactly the same things and one is 6'5'' and one is 5'5'', you're going to err on the side of the 6'5'' because of the nature of the game,'' Gaze says.

''But if the 5'5'' guy can do things better - he's quicker, can dribble better and is a nuggety defender - there have been examples that he can be successful.''

Sheehan says genetics do matter to a point in the AFL.

''You don't have to be super quick, you don't have to have super endurance but you need enough of those things to get to the elite level. You're relying on your parents there,'' Sheehan says.

''If they've given you great speed like Chris Judd then that's a helluva of an advantage too. Nature plays a role but it's then up to the coaches.''

Chappell, however, has no doubt talent is nurtured rather than inherited.

''That's why there's so few sons and daughters of champions that become champions themselves,'' he says.

''If it was about nature you'd think that everyone that's had a sporting pedigree would just throw out these great sporting kids.''