Let me guess...you've never actually read the Constitution, have you? It says no such thing. This is the entirety of what it says about presidential qualifications:
"No Person except a natural born Citizen, or a Citizen of the United States, at the time of the Adoption of this Constitution, shall be eligible to the Office of President; neither shall any Person be eligible to that Office who shall not have attained to the Age of thirty five Years, and been fourteen Years a Resident within the United States."
Do you see the word "parent" or "parents" in there anywhere? Of course you don't.
so what is the difference between a natural born citizen and a citizen? Why did they put that wording there? Does it mean anything other than citizen?