These are one of the funniest kind of jokes because the Medical profession is otherwise a serious profession.
A man walks into his doctor's office and sits down in the waiting room. While he is waiting his turn to be seen, a casual acquaintance walks in and sits down next to him.

The newcomer asks, "W w what are yyy you ddd doing here?"

The man replies, "I am waiting to see the doctor."

"W wwhy dd do yyy you wwant to sss see hhim?"

The man replies, "Well, if you must know, I have a prostate problem.

"A pp prostate ppp problem, wwhat's ttthat?"

"Well, if you must know. I pee like you talk."