A bizarre thought came to me about this “natural born” issue. What about sperm donations...who knows where that originates? Naturally, the mother (sometimes a single parent) using the sperm donation would probably be natural born, but who and what is the nationality of the Daddy? Don’t suppose it would matter in a surrogacy situation, as the woman carrying the child is basically just hatching it. The “natural born” issue I am afraid is going to go by the wayside, being assailed as it is on all sides. Both Romney and Santorum have questions in this regard, as does Jindahl & Rubio if they have future Presidential aspirations, that I can think of offhand...not to mention the offender in chief, Obozo in the White House.
It would be impossible to prove one is eligible as a natural born citizen if the citizenship status of the father is unknown. Thus, the burden of proof, which is on the one seeking office, could not be made. Not eligible.