Technically, the pronoun "he" doesn't always have to be male. If you do not the gender of who or what you are talking about it IS grammatically ok to just say "he, him, etc." as a kind of shortened of version of saying "He or her, his or hers, etc." Since Pokemon DO have genders (the ones we are referring to anyway) then it is more correct to say "he" than "it." for a Pokemon that does not have a gender, then you would say "it" or whatever the hell people say these days.