Kid's sports - age or size ?

The traditional way of grading kid's in sporting contests has been age.  This incorrectly assumes that kids of an equal age - are also equal in size and weight, and today that is a very wrong assumption.   It may have been roughly a measure when the Australian population background was from England, Scotland, Ireland or Wales - but that is no longer the case today.

We are now seeing a huge disparity in weight and height between kid's of a similar age, and this is having a negative effect on sport.  Many parent's are reluctant to allow their kids to compete in contact sport because of the chance of injury and this is also a disincentive for smaller kids to put themselves at risk.

We are now a mixed, multicultural population and ethnicity has a bearing on body size.  How do you compare kid's from a Polynesian background who tend to be giants - with kid's from an Asian culture such as Vietnam - who are so much smaller - and expect them to compete on equal terms on a sporting field ?

There are calls to dump age as the criteria and develop a new measure which takes into consideration the weight and size of those expected to compete together, but this would obviously introduce new challenges.
Body size and mental maturity have little in common.   Just as kid's school classes grade mental learning on an increasing scale, so tactics on the sporting field are geared to mental development.

An older kid - several years more advanced than a younger kid of the same size - would have an added advantage in a skill contest, and yet they would be considered equal by a comparison of body size.    There would also be another factor to be taken into consideration - and that would be the type of sport involved.

Kids playing Rugby football have a distinctive size advantage if they are big because of the tackling involved in that game, while those playing Soccer may have an advantage over a bigger opponent because of a speed advantage and absence of brute force tackling.

Pity the sports administrators who have to work out some better form of grading.  The probable answer is to retain the age system, but with the provision that the twenty-percent of players who form the extremities of too big or too small be encouraged to choose a different sport where size does not matter.    Perhaps swimming or tennis rather than a contact sport !

Whatever system evolves, it is certain to raise new contentions !