Is Haku male or female

Male Haku was being referred as Male in all of the Naruto episodes. If Haku was female, and they were wrong in the first time they said that Haku was male, then they should have referred to him as a she in another episodes. wikis and encyclopedias said that Haku was male. Haku's voice sounded like a boy's voice when the episode showed his flashback of being a child before Zabuza adopted him.