Probably done to death, but:
I'm kind of curious how something like this would play out -- What if Charles VI had a son a few years after the birth of Maria Theresa? I know the Pragmatic Sanction of 1713 was already in place at the time, but the birth of a male Hapsburg would certainly change it.
So, let's say that this male is born in... 1720-1721 (making him 19-20 by the death of his father).
What kind of effects do you think this has on Europe?
Does Prussia ever get Silesia?
Does Austria have a bit more power come Napoleonic War (if it happens at all?)
I'm not very well versed at the whole medieval/Renaissance European blood politics, so I'm asking y'all.