Why is the male organ called the penis at the doctor, and you can not say "pee"?

The male organ bears the name "penis" in anatomy, and in Latin it is "penis". It can be said that such phrases are "professional" and unequivocally determine what part of the body is meant. The word "member" has also become widely adopted in Polish. "Pee" is a very colloquial phrase, often used to communicate with children, who find it easier to explain that boys have a "pee" (which they urinate) than a "penis". At the doctor's visit, you can use such vocabulary as you think is appropriate, which is free for you and allows you to convey all relevant information about your health condition. Perhaps, however, it is worth convincing yourself to use more professional words during a medical consultation, if you know and understand them. In my opinion, such behavior will be more appropriate to the situation. The decision, of course, is yours.