I tend to think of it as a *person* filling a role that was missing from your childhood. As you peel away layers during therapy and find these painful absences in your past, we let the compassionate and empathetic T fill that role as we re-live the experience. So in the context of transference, it's the missing need that is filled, rather than specifically replacing a mother. In this way, the word 'maternal' or 'paternal' doesn't matter. Because mothers are the primary care-givers, maternal transference is so much more common.

Just my opinion.
-P
PS. I just read Starfishing's excellent post...I guess I should read rest of the thread before posting. I already wrote it so, so up it goes