I personally believe Crona is a boy,it's just cuter that way to me <3 Though,in my perfect little world,Crona stays genderless forever.That way neither fan base has to get crushed by Crona's true gender being revealed.If Crona were a guy,girl Crona fans would be crushed,if Crona was a girl,guy Crona fans(including myself) would be devastated.So I think its best it is never revealed.To me Crona is male,that is what i'll always believe <3 no matter what anyone says.