Most of the people voted at
yahoo answers that
Haku is a boy who dresses like a girl.One of them was also saying:"
Haku is a boy but had me fooled until
Haku seen
Naruto checking him out and he told
Naruto he is a boy.
Haku can easily pass for a girl though.
Naruto was trying to concentrate his Chakra to his feet so he can climb a tree and while doing that,
Haku was also in the forest so that is how they had the conversation.
Kakashi told
Naruto, Sakura, and
Sasuke that learning to climb up a tree while concentrating their Chakra in their feet would help them in their training to defeat Zabuza."