Is Michael Phelps retarded?

I see his picture every time I go in the kitchen since his picture is on the box of frosted flakes. I know he must be able to tread water like a dolphin but he looks like he fell off the short bus. I feel sorry for the poor guy because if it wasn't for the olympic medals he would never get laid. Am I the only one thinking this? Should he really go back to the special olympics?