MUCH as we would like to think of stardom as the product of talent, courage, application and — grudgingly — genealogy, it is possible that it simply is written in the stars.

A Melbourne football enthusiast has studied AFL lists and found a bias against players born later in the year, especially in October, November and December.

An insurance broker and Melbourne fan, Mick Todd, notes that there are, for instance, 66 players born in January and 68 in March, but only 44 in November and 38 in December.

These statistics are not merely accidents of birth. The cut-off age for most junior sport is December 31, which means those born early in the year are older and generally physically more mature than the balance of their age group.

There is a body of evidence to say that this wins them more notice and greater favours, and at the elite level makes them more appealing to recruiters.

In the AFL, the effect is sharpened by the fact that to be eligible for the draft, a player must be 17 by April 30, bunching up draftees' birthdays into the first part of the year.

Next year, the cut-off date will be advanced by four months to December 31, bringing it into line with under-age competitions.

The top 10 from last year's draft makes for a crude but instructive sample. Nine were born in July or earlier. The previous year, only two of the top 10 were born after August.

The AFL is acutely aware of the horoscope syndrome. In an exhaustive report on recruiting commissioned by the AFL last year, former Hawthorn recruiting manager John Turnbull wrote: "It has been hypothesised that older players were bigger, stronger, faster and better co-ordinated than younger players, and thus experienced more success."

A previous study of draft camps over six years conducted by, among others, national talent manager Kevin Sheehan, discerned a "clear bias" towards early-birth-month players. Noting this, Mr Turnbull said: "It is clear that players with a late-season birth month have been disadvantaged. The effect of this disadvantage is still evident in the distribution of birth months in senior contracted AFL players, suggesting a long-term or residual birth-month effect."

Mr Todd presented his findings recently on Sportzfan Radio on Southern FM. His curiosity was piqued by

an article in Slate, an online magazine owned by The Washington Post. The article demonstrated that a baseballer born in August had a 50% to 60% greater chance of making it into the big leagues than a player born in July.

It shows that as surveyed by birth date, the likelihood of a player reaching the majors peaks with August babies and declines month by month until July. The article surmises that this is because the cut-off date used by nearly all junior baseball leagues in the US outside the majors is July 31.

"Twelve full months of development makes a huge difference for an 11 or 12-year-old," says the Slate article author Greg Spira. "The player who is 12 months older will, on average, be bigger, stronger and more co-ordinated."John O'Callaghan, a lawyer, Southern FM presenter and try-hard footballer, says the same syndrome is observable in Australian sports. Bigger, older players dominate in juniors, and the imbalance often is not redressed until adulthood.

By then, it is too late for some. "One thing we do know about is the undeniable advantage one gets from confidence," Mr O'Callaghan said. "If you're getting game time and being told you're great, how much better is that than getting little game time and the feeling of failure and inability to compete? And when you extrapolate that over 10 years or so, it's a fairly powerful force on a kid."

The science is inexact. It deals in generalisations. It does not allow for conflicting data on what is the most common month to be born, anyway, regardless of sporting prowess.

And it discounts the precocious talent who is years ahead of his age, in any case, and would always be a star.

But it is hard to ignore. Mr Todd also surveyed players in the TAC Cup, the under-18 competition. He discovered an almost linear decline over the course of the year, from 63 March babies and 57 April babies to just 29 born in November and 25 in December.