That's what his birth certificate says. But it is a Canal Zone, not Panamanian document, and Colón was the nearest town to the naval base.
Someone really should ask his mother about it. She does relate hearing the celebration at the O-club after John IIIs birth, but of course that could have been after she and little Johnny went back to their quarters on Coco Solo.
It's hard to believe that if their baby would not be an American citizen if born in the local hospital, that someone like the McCains (father and grandfather Annapolis graduates, and eventually Admirals) would go there in an era when home births were fairly common. Unless there was some indications of a "problem pregnancy" of course. And if there was, I'd think they'd evacuate the mother to be to the nearest *American* hospital, which was likely in the Canal zone. B
The question is whether he is a 'natural born citizen'.
The answer depends entirely on the exact constitutional definition of 'natural born'.
A lot of people claim they are the sole arbiter of that.
They aren't.