Micropenis Threshold?

So my friend has a small penis and was wondering what exactly is the cut-off point for having a micro-penis? My friend is far too terrified to Google image search this and I can't either for entirely different reasons. I feel bad for him because my penis is extremely large and very satisfying to women and definitely works perfectly all the time, so I wanted to help him answer this question. He says that if he's at least a little above the threshold it might make him feel better.

Also, who is the piece of **** Doctor that coined the term "micro-penis" and why is it even considered a medical issue? Under what circumstances would a doctor even diagnose this issue? What does that conversation sound like? Is the doctor held responsible when the patient immediately punches him in the face upon receiving this diagnosis? These are all things my friend is curious about.

Thank you for reading, and again, just to be clear,my penis is huge and wonderful.