Yes I play banjo as accompaniment for my voice, but I agree with McGrath that I've never thought of GIRL keys. And I'm a soprano - as girlie as it gets. The trick is the same as for males - find a key that sounds good, that you can sing the song your working on in, and go for it. Find a list of tunings and do the rest by ear. For me I often find myself in song sessions, lining up with the bases to sing harmony bits - that's where I fit best. Bit wierd but no one minds. When you are singing and playing solo your options are limitless. Banjos are great with women's voices - and with male's - or dog's - or bird's. Banjos were made for songs.