Is it true that all witches are women?

The male equivalent of a witch is called a "Warlock"; however they are all collectively called Witches; male and female.

Answer

The word Warlock is thought to derive from the Old English w«£rloga meaning "oathbreaker" or "deceiver." It is not an alternative for the term Witch, originating in all likelihood from late middle English Scotland, where witches were termed oath breakers as they broke their oaths with the Christian church. In actuality, practitioners of Witchcraft are correctly termed "Witch" regardless of gender.