This is "natural" in a legal context not a biological context. What this generally amounts to meaning is that you met the requirements of being a citizen when

This is "natural" in a legal context not a biological context. What this generally amounts to meaning is that you met the requirements of being a citizen when you were born. This doesn't specify a method of birth (cesarean or otherwise), but instead that you're either born to existing citizen parents, on us soil, or on otherwise recognized us territory (Puerto Rico, military bases, embassy grounds in a foreign country I think also can count) and I believe I've heard that an exception to this is that you're not being born to diplomats on official foreign government business, because not all countries recognize dual citizenship and forcefully giving the newborn US citizenship could cause diplomatic issues with the other country.