Thanks, he is definitely a boy. I was confused when naruto refered to him as sis in the flashback but he was refered to as a boy
^ My point exactly. :u"Mister… you have the same eyes as me…" (お兄ちゃんも…ボクと同じ目してる…) ("Onii-chan mo… boku to onaji me shiteru…")
Here is the proof that he's male. Men in Japan use "boku" when they say something about themselves. "Boku" is the equivalent of "I".
Of course "boku" is not used much, because most of the times it's clear whether they are talking about themselves or about someone else, but they do use it.
Women use "atashi" if they are explicitely referring to themselves in a sentence.