Donald Trump speaks to the press during an announcement that Trump is investing in the development of luxury properties in the country of Georgia at a press conference in New York on March 10. (LUCAS JACKSON/REUTERS)

In a radio interview on Fox & Friends, Trump defended earlier claims that the president’s citizenship documentation was in doubt (it isn’t). “You have no doctors that remember, you have no nurses — this is the president of the United States — that remember. ... He could have been born outside of this country. Why can’t he produce a birth certificate?”

Trump first made the “birther” claims last week on The View . “I brought it up just routinely, and now I’m starting to wonder myself whether he was born in this country,” Trump said Monday. Trump went on to volunteer that his own birth certificate was “sitting on the top of my desk.” Asked if he thought the president was born in the country, Trump said he was “really concerned.”

Trump’s claims appeal to a certain segment of the populace who believe the president was born outside the United States, despite ample proof that he is an American citizen. During Trump’s appearance on The View, actress Whoopi Goldberg called it “the biggest pile of dog mess I’ve heard in ages.”

The Washington Post’s Chris Cillizza reports on why Donald Trump is most likely not serious about his presidential bid — birth certificate claims aside.