it's understood that a person born of parents of a certain nationality is under the jurisdiction of that nationality. 2 mexican parents = kid is mexico's problem regardless of location of which they were born. this also works the opposite way 2 american parents = kid is us citizen and the us's problem even if born in mexico or other country, this applies even if the country they were born in grants automatic citizenship. it just means the child is now a dual citizen. if the birth country allows for that upon the child coming to the us and being granted citizenship.
United States