That Mewtwo is clearly female
No, according to movies, Mewtwo is male. He even had male voice actors that did his voice in the American 4kids dubbed versions.
Edit: I saw the Japanese Pokemon: Mewtwo's Awakening Trailer. This is what I have to say, "What?" x10. Seriously, according to the first two movies, Mewtwo was supposed to be male...
If it turns out to be an entirely new Pokemon, like another successful recreation of Mew, only in Kalos instead of Kanto, that'll be much better than simply a new form of Mewtwo.
That Pokémon is a form of Mewtwo. This forme of Mewtwo is called the Awakened forme. This was confirmed ages ago if you didn't know already.
Damn, that sucks, Mewtwo didn't need a new form he was cool already... Yeah I'm way behind on X&Y news for some reason. I've got some catching up to do.
I go to Serebii every now and then, but I mostly go to Bulbapedia for my news and general Pokemon information. I tend to avoid news gathering here on this forum because it's rife with rumors and I'm not sure what is true or not... like that Light-type rumor running around a few months back.