Responding to the three posts above:
I agree with Herbho, for the cost of a glove and some lube and a few seconds, I, too, would say, why take a chance? There are prostate cancers that are discovered through the rectal exam. And I have personally - not on discussion boards - personally known a case of prostate cancer in the 30s and the 40s, so maybe my doctor wasn't so crazy doing them in my 20s.
As to Tenn77's post, that is not how a prostate exam is supposed to be done. I have never had one that hurt or was uncomfortable. If the doctor uses enough lube and takes his time, his finger should go up gently. And unless your prostate gland is infected - in which case you might feel some pain - when he is feeling your prostate all you will feel is that you might have to pee or cum, neither of which happens.
And Hou_headhunter - all of us have the right to refuse a medical procedure. The doctor can explain why he wants it, but he cannot force it upon you. That's the law. However, if you just relax and let the doctor do his thing, it is an easy exam and over in seconds.
I would much rather get 10 prostate exams than have one tooth drilled !
One thing that is missing from all of these discussions is that during the RECTAL exam, the doctor does the prostate exam but often is able to pull out a sample of feces which he spreads out on a special card, and puts a special solution on it, which will show the presence of blood in your stool, which can be the first sign of colon or rectal cancer. That happened to me one time during my rectal exam, the card showed signs of blood in my stool. I suspected, and it turned out to be true, that the blood was from nose bleeds that I was having because of dry air caused by heating. But again, that is one of the most simple tests you ever will have, so why not have it?