To confirm Beachbum's story, Kitty is a boy.
From my recollection, some user created the account without reviling too much about their gender (kitty is a pretty gender neutral name, though it does lean towards the feminine side). The user stumbled upon AoT, then decided to revile that "she" was a girl. When she started this topic by posting a pic of herself, not too many people doubted it (myself included). However, there were a few who had played with her in AoT that doubted this ruse and set out to disprove it. Long story short, Kitty (or someone else) ended up revealing that she was infact a he and was stealing someones pictures (they were thought to be his sister's).