That's like the joke with the priest that knew all the wines:

There was this priest that knew, just from tasting a bit, what year, brand and country any wine was from. One guy, curious if he could trick the priest, took a glass of urine from his 16-yr old daughter [presenting it as a rare white wine].

The monach said: "16, blonde, virgin. But she's not from my community"

==

Or well, something like that...