If under-25s are too neurologically underdeveloped to make decisions that affect their body and wellbeing, then that rules out all career athletes under that age. You can't possibly let a 18 year old take up a sport that comes with significant concussion risk, surely?
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Also, let's follow the logic to its conclusion
If having a brain functioning at its peak is a requirement of making important decisions, then it's probably more important to have a *maximum* age limit than a minimum. Because the older you are, the more your brain wears out
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