Does anyone remember the Bangles? They didn't make a big issue out of being an all-girl band, they just made good music.

As for the pitch of the lead singer's voice, that gets taken into account during the song-writing process. Lee Aaron, Sass Jordan, Alannah Myles, Toronto, and The Headpins are all Canadian heavy-rock bands built around female vocalists.

In the USA there's Melissa Etheridge, Heart, Hole, Seven Year Bitch, Biff Naked, Bonnie Rait, and probably a bunch more who don't get up this way very often. The point is, Women who rock, rock just as hard as the guys do. There just don't seem to be as many of them. (Maybe they have better sense! :D )