Mimitchi is well a female, Mamaetchi is the male, Memetchi is the female, Kuchipatchi,male,Violetchi-female...these are the main mascots of tamagotchi hope i helped!!
It depends on what version of Tamagotchi you're talking about. On V4 and 4.5 it's female, but on V3 it can be male or female. I'm not sure about V1 or V2 though.