This is part of Haku's profile that i found on the net. So yeah, he's a guy.
Haku was born in a perpetually snowy village in the Land of Water. Although he lived in peace for a time, Haku eventually discovered that he had inherited a kekkei genkai from his mother, an ability that was irrationally feared at the time. Once Haku's father learned of their gift he rallied a small mob and had his wife murdered. He would have done the same to Haku, but Haku inadvertently created a field of icicles through the house in a panic, killing both the mob and his father. Orphaned, Haku wandered the Land of Water as a beggar child until he was found by Zabuza Momochi, who agreed to take him in as a tool, warning Haku not to expect any companionship. Haku readily accepted this role, devoting his life to becoming the ultimate weapon for Zabuza. Over the years Haku was trained by Zabuza and in time became fiercely protective of him, so much so that he would not allow anyone to touch him. In his devotion to Zabuza, Haku finds purpose in life only by being of use to Zabuza, and does whatever is asked of him to continue to give his own life meaning.