It's how quickly you travel over the border.
Chivas and Jesus Padilla now have their story straight. In this article on mediotiempo, They both acknowledge that Jesus was born in San Jose, California. However, they add that he went immediately, within two weeks, to Mexico, and got a birth certificate there. That seems to stretch the definition of "birth certificate", since a person can only be born once in one place. There's also no way to verify the claim of when they traveled across the border, even though it's hard to believe a family with an infant and a mother who has just given birth suddenly feel like traveling to a tiny town in Mexico.
Anyway, the gist from their viewpoint is that there's no problem at all. To play for Chivas, you don't have to be born in Mexico, after all. That's just a technicality.