To use a derivative like "mentee" is to pop the lid off Pandora's Box and loose all manner of unfortunate "words" on an unsuspecting world. If mentor is used as a noun meaning wise counselor or guide, it soon becomes a verb meaning "to teach, to instruct, to direct." If nouns which end in -er or -or are facilely turned into indirect objects -- e.g. lessor/lessee, condemner/condemnee -- then it is a short step from "mentor" to "mentee."

Once the lid is off, one must make expect and accomodate the absurd constructions which will follow:

mentoration -- the act of guiding or teaching
mentorially -- in the style of a guide or teacher
enmentorment -- guiding or teaching
polymentoricity -- having many guides or teachers
mentorrhoea -- too many guides or teachers all talking at once.

Don't let this happen to a language you love.

Father Steve
(who posts only 1.375 times per day, on average)