It's very common for circumcision defenders to demand proof that the foreskin is pleasurable, functional, or whatever. Often they will demand you provide scientific studies, link the AAP's lukewarm praise of circumcision, and then try to paint you as anti-scientific. But what they are doing is shifting the burden of proof to where it doesn't belong. I'll illustrate this with an example.

Say I want to cut off your finger. Does the burden of proof lie upon you to show that your finger is useful, functional, or whatever metric I demand? Of course not. The burden lies upon me to fulfill at least one of two very specific demands. Either:

  1. The finger poses an imminent, catastrophic danger to your health. (Like life threatening gangrene, not "20 years from now when you're having unprotected sex with your HIV infected partner...")

  2. Or you've asked me, in writing, to cut your finger off.

That's it. And this applies to literally every part of the body except the male foreskin. You don't have to be an expert to understand why society should guarantee this basic protection. This is pretty much the bare minimum of why medical ethics or human rights should even exist.

So while it is helpful to demonstrate that the foreskin does indeed have value and function, don't feel that you have to or that you're some kind of science denier if you don't. There's nothing wrong with shifting the burden of proof back to where it actually belongs. So when someone demands that you prove how pleasurable a foreskin is, ask instead that they prove how dangerous it is to have a foreskin. If they want to cut it off without consent, they must demonstrate a real danger to health, not just that it's "ugly", "excess", or "dirty". This is the only science necessary to decide the question.