User blog comment:Dark Knight 178/Stop giving Genders to Pokemon. It is very Annoying./@comment-6632076-20150518203423

Pikachu confirmed male

Mewtwo is genderless with male voice

Jigglypuff confirmed female

Lucario has male voice

Charizard is generally accepted as male and has been referred as male

Greninja is the only really unknown one, but it's probably male