So I was looking up ash's butterfree from the TV show the other night.
In lets go Eevee, female butterfrees have a black lower wing. [Check the pokedex to see this]
Well....looking at ash's butterfree, it looks like it's a male butterfree, because it does not have a black lower wing. The butterfree it chose is also male, because it also does not have black on its lower wing.
So...Either ash's butterfree is Gay, or this is a massive plothole on their part.
https://pokemongo.fandom.com/wiki/List_of_Pok%C3%A9mon_gender_differences 