[HerenIstarion]

Quite an interesting turn. I too always presumed Malbeth to be a man. Now I've made a quick search, and found that Malbeth is never referred to as he or she whatsoever. (If I'm correct in my calculations, Malbeth is only mentioned two times in LoTR, and besides only in HoME VIII). But I stll tend to presume Malbeth to be a man, since:

a) otherwise he would have been referred to as seeress (i believe)
b) the other 'seers' to be met in Tolkien's works (except creatures of non-human origin)(that is, Tar-Palantir, Michael Ramer and Edwin Errol) are all men