>>22105908No anon, they do change.
To determine gender, a random number is generated to represent the percentage between genders.
So since azurill is 25% male and 75% female
any number generated between 1-25 makes it a male,
and any number generated between 26-100 makes it female.
This number remains in the pokemon data and isn't altered even for evolution
So since marill is 50/50 if the number rolled for the azuril is on the female side between 26-50 then when it evolves it will be in the male side and the game will show them as male. So 1/3rd of all female azurills will evolve into male marills. Seriously try it.. makes giving a female name to an azurill seem kind of weird when it evolves.