The laws in effect at the time of birth determine whether or not someone would be an American citizen at birth, which is what “natural born citizen” means. A non-natural born citizen would be one that has to get “naturalized” to become a citizen.
Here’s a link to the laws & the changes that have gone through in the 20th century.
http://www.americanlaw.com/citabrd.html
Show me the constitutional reference, please?
A mere law does not overrule the constitution, the constitution is the SUPREME LAW OF THE LAND.