Why are the rules different for boys & girls & should it all be the same.

Not to hijack the thread, but even the colleges have adaptations or modifications of the NCAA rules (or least they did in the past). Example I give you would be the NAIA (in the past, when I was in college) allowing pre-game dunks even if the NCAA rulebook said it was illegal. It was kind of funny watching my alma mater dunking in pregames while a rival that was NCAAIII couldn't. There's also the adaptation at the JUCO level that the officials can wear the grey pinstripe shirts instead of the black and white striped shirts.

So the semantics if rules that are modified are modifications or adaptations or whatever are moot. They are rules in the jurisdiction in which they are used.