Male fairies are referred to as fairies. No gender differentiation exists. According to legend, there are dozens of types of fairies, some of which are predominantly or totally male.
The leprechaun, or clurichaun, associated with drinking and the pot of gold is a sort of masculine fairy. Red men, or fear deargs, are associated with horrible practical pranks and nightmares, and it is believed that a similar male fairy, the redcap, must bathe in blood in order to survive. The brownie is a friendly male fairy who performs cleaning and tasks in exchange for cream.
There are also a handful of female-only fairies, such as nixies, banshees, and leanan sidhe.