Okay, so I traded with my friend who uses White, I traded my Cottonee with his Petilil, when we first traded my friends Petilil was female. When we were finished trading, my friend left and then when I play my game the Petilil turned male!! What's going on? All Petilils are supposed to be female!!!
Well I have never seen this happen before, it must be a glitch becuase petilil is only female. Petilil is 0% male and 100% female.
source
-Wither