Being born in the USA is “necessary but NOT sufficient” part of one being a “natural born Citizen of the United States” to constitutional standards. One’s parents must also have been Citizens of the United States, either born Citizens or naturalized, when the child was born in the USA for that child to be a “natural born Citizen of the United States” to meet Article II section 1, the presidential eligibility clause in the U.S. Constitution. The founders and framers considered allowing simply a born Citizen to be eligible but they rejected it and elected to require only a natural born Citizen. That extra adjective means something.
See my post on 17 Sep 2011 – Constitution Day 2011 – A Lesson from History: Is Being a Born Citizen of the United States of Sufficient Citizenship Status to be President of the United States and Commander in Chief of Our Military? The Founders and Framers Emphatically Decided … It Was Not!