Section 1 of Article II of the Constitution of the United States says, in pertinent part:
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; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty five Years, and been fourteen Years a Resident within the United States.
The Twelfth Amendment to the COTUS says that no person who is not eligible to be President shall be Vice President. So, the Vice President must also be a natural born citizen, at least 35, and a resident within the U.S. for at least 14 years (wow--should be longer, IMO).
Another part of the Constitution made every resident of the U.S. at the time of adopted of the Constitution a citizen of the US and the above makes such citizens eligible to be President, even if they were born elsewhere. (Ergo, the above made someone like Hamilton, who was born in the West Indies, eligible to be President, though he never was.)
However, all members of that group are long gone, unless you believe in immortals or the formerly dead. That leaves us with "natural born citizen," a term that the Constitution does not define. But, the term, on its face, seems to have something to do with birth.
Notice, though, that the above quote never mentions place of birth, something that seems to have eluded the likes of Trump, who apparently gets his knowledge on the subject who doesn't know the Constitution from third base.
The SCOTUS has never squarely decided what "natural born citizen" means in the context of Article II of the Constitution. However, in cases not interpreting the Constitution, the Supreme Court has said that, historically, a person born within a nation would be considered a natural born citizen of that nation. The SCOTUS has never said, however, that the ONLY way to be a natural born citizen of the US is to be born within the US.
I have not studied the history of this issue, even a little. However, it's inconceivable that someone whose parents were citizens of, say, England, would not be a citizen of England if he or she had been born abroad because the parents were spending time at a vacation home on the Riviera, for example.
Hence, McCain, who was born outside the US to a mother who was a US citizen and a father who was a US citizen, was eligible. (Some argued that he was eligible because he was born on a military base, so that means he was born in the US. I don't think that is the reason, though.)
Is one parent enough, though? Probably. So many members of the military have married women born abroad, when stationed abroad, or fighting abroad, or occupying a nation. That was probably so throughout history. It would be unimaginable to deny such babies citizenship. I believe that Gomez's mother was a US citizen. So, even though Gomez was born in Canada, he is eligible to be President or Vice President, as far as Article II is concerned.
What if neither parent is an American citizen AND the baby is born outside the US? In that case, unless the language quoted above is amended, I think the baby can never be President, even if he or she and the parents later become citizens. (So sad, Swartzenegger!)