"The weight of legal and historical authority indicates that the term 'natural born' citizen would mean a person who is entitled to U.S. citizenship 'by birth' or 'at birth,' either by being born 'in' the United States and under its jurisdiction, even those born to alien parents; The predominant legal scholarship holds that the term natural born citizen applies, quite simply, to anyone who is a U.S. citizen at birth, or by birth, and does not have to go through the naturalization process. The child of parents who are U.S. citizens, regardless of whether he or she is born abroad, fits into the category under most modern interpretations."
https://www.thoughtco.com/presidents-not-born-in-the-us-3368103