Tracy Chapman, Billie Myers, Doris Troy and Cher: Female Tenors?

I don't know about anyone else, but I think female (tenors?) sound really neat. It's a nice contrast from the mezzo soprano vocal gymnastics that are a dime a dozen in the music industry, and have especially become rampant (erm... Whitney wannabes) concerning black artists. I'm just wondering is they are called tenors or something else.