always a boy
I don't think it really matters to the general public whether Tyrannosaurus Rexii (Rexes?) can be distinguished into males or females because stereotype dictates that all T. Rexii will always be portrayed as grotesquely ferocious, with the downturned brow and the shiny razor teeth dripping with saliva, and this same stereotype will ensure that the general public will assume this colossal beast to always be male, despite its adorable tiny arms. I've never seen a pretty T. Rex, with long, curled eyelashes and a sweet toothless smile. Have you?