Let’s cut to the chase, shall we? The Constitution says, “No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President...” Where does the Constitution define ‘natural born’ as only those physically born in the United States to U.S. citizens?
I never defined it as such. I would personally like it to be defined that way but I've seen nothing that disqualifies an anchor baby from having natural born status.
One can only deduce the definition of "natural born" by reduction. Since it was deliberately determined by Congress that John McCain's citizen status is not "natural born", we are only left with one remaining qualifier for the natural born status and that is: to be born in the United States.
I'll point out that the term wasn't totally explicable even back then. If its meaning was obvious, the 1st Congress wouldn't have felt the need to include the qualifying language. They later on deliberately repealed the extraconstitutional qualifiers.