Unless I'm remembering wrong, there ARE females in this world, we just don't interact with many of them. The Brothel Madame, for instance, doesn't have a penis, and I don't think the nun in the church has one either. Also the angel at the Altar location, but being that she's an angel that's not exactly the same. One of them 2 vampire sisters (the thicker one) is full female as well, with a vagina and everything: in the threesome scene with them you get sandwiched between the 2 of them.