If you are a natural born citizenship, then proving your citizenship is proof that you are a natural born citizen.
Is a “duh” needed here. You seem like a smart fellow.
No, you are incorrect. I have proven my citizenship (to get a passport, for example) but have never proven my natural born citizenship. No one has ever asked to review the citizenship status of my parents.
I thought that being born in this country of citizen parents was the definition that is being used by most birthers.