Just because you are a Citizen doesn't mean you can be President.
As a Naturalized Citizen you can hold other Government offices but not the Office of the President.
I am a U.S. Citizen, as is the Gov. of California, Arnold can't become the President neither can I.
I Don't think that should ever change.
Why it has been acceptable for Obama to refuse to produce a birth certificate I will never understand. It's been the same thing with the question about him being a Muslim.
I tend to believe what my Muslim friends have told me in regards to a child born to a Muslim and then living in a Muslim country with a Muslim Step-Father.
Personally I don't care if he is Muslim, but those that were outraged at the mere suggestion of his faith being Islam I think would have a very big problem with him being Muslim. Just like you couldn't even mention his middle name being Hussein during the campaign. Then all of a sudden when he won the election it was ok.