Yup I knew tortoiseshell cats were female. I also thought white ones were too, but they're not, as I thought ginger cats were just male, but they're not either. I had my Ginger Tom, Jasper, for 21 years. Never to be replacedHaha. I love tri-colour/calico cats.
Random fact I only learned last year: tri-colour and tortoiseshell cats are almost always female, because it requires two X chromosomes genetically.