I bet you thought there was no away even the most creative researchers could design a before-and-after study examining the effects of circumcision on sexual enjoyment. After all, it's not like the volunteers would be lining up for standard study compensation: fifty bucks and all study-related medication.
But actually, in Uganda, where adult men are getting circumcised as a way to reduce the spread of HIV, researchers were able to ask thousands of sexually experienced men whether circumcision reduced their pleasure. And virtually 100% reported no problems following the procedure.
Thank God. Or else I would have had a lot of explaining to do to my nice Jewish sons.