"Trump does not practice Orthodox Birtherism, the belief that no proof can possibly exist to validate Obama's existence. He's a Reform Birther -- "I really believe there's a birth certificate," he said, but the doubts are a "terrible pall." His theory: "There's something on that birth certificate that [he] doesn't like."
Weigel : Donald Trump Wants to See Barack Obama's Long-Form Birth Certificate
http://www.slate.com/blogs/blogs/weigel/archive/2011/03/24/donald-trump-wants-to-see-barack-obama-s-long-form-birth-certificate.aspx (Accessed 24 March 2011)