Very interesting is this phenomenon. Malcolm Gladwell writes about it in his book 'Outliers' which is an amazing read that I recommend all read. What he identifies is that in professional sports there is generally a calendar window where the most successful players come from. This is often those with birthdays early in the representative year - as when they are growing up, they can be up to a year older (and therefore more physically developed) than those they are competing against. Over time they begin to win representative positions and have access to additional training, more tuition and coaching. From there it snowballs, they continue to get better as they work more. Eventually they hit the pros and theyre drafted and from there get even more training and go on to become superstars.
So while the thinking may be take a younger kid because they have more development, it's no guarantee that they'll be better than the older kid and that they're merely 6 months behind in development, it could be that they havent had the same development of the older kid thus far and might never be able to catch up.
This is the reason why I will be planning the birth of my future children around representative football age qualification windows
All AFL Players Broken Down by Birth Month - Draftguru
The link above suggests to me games played is not correlated to birth month, but the number of draftees is.






