It has always bothered me that people call some Pokemon "gender-less," because it just isn't canon. In every pokedex entry, Pokemon book, and any other official resource has listed them as gender unknown. This implies they have a gender, they just haven't been identified. (Because Pokemon are clearly not void beings)
So, what is it: do they have genders, or don't they?
The difficult part is if they did, why haven't they been identified? This could be chalked up to the scientists never seen them breed or anything, or in legendary's/mythical's case, could be that they are infertile. Then, why are [email protected] and others gendered? They are not the only ones referred to as being clearly one gender and not the other.
Please try to use canon reasoning. Thank you!