Under Mexican law, a person born in the US of Mexican parents is automatically a Mexican citizen.
Actually, that is a pretty common situation.
Turkish Nationality Law (Interesting point of trivia -- a common situation is for Turkish guest workers in European countries is to return to Turkey for a year to complete the requirement for them to do a year of military service needed to retain their citizenship and then, once that is done, to go back to their foreign "home" -- that resulted in a lot of Turkish conscripts who barely speak Turkish)