Herbert Hoover’s mother was born in Canada, although she may have been naturalized by the time of his birth. The previous poster is correct, however, that anyone born on American soil is an American, regardless of parentage. Even a child born outside the United States with an American parent is an American, as was the case with George Romney and John McCain.
I will qualify your statement to say that I agree, based on the changing rules in force during our history.
The AGE of the parents, and their residence in the years prior to the birth, and years of residence here, does make a difference and the laws have changed several times.
Natural Born Citizen means Citizen at the Moment of Birth.
The laws for NBC on foreign soil can and have been changed, by Congress, several times.
Canadians are Americans, Mexicans are Americans...
Hell, people living on the very tip of Chile are Americans.