The study of the elusive micropenis; the natural science concerned with the structure, growth, origin, evolution, distribution, and taxonomy of micro-penises. Someone who studies micropenology is considered a micropenologist.
A: "Did you see that guy's micropenis?"
B: "No, I couldn't- it was just too small!"
A: "Well, if you would have majored in micropenology, you would have been able to"