There's been a whole lot of fuss made over a couple of athletes in the Olympics who don't appear female enough to satisfy some people that they are in fact women. I'm not going to link to the various stories on the specific incidents in part because I do not wish to contribute further (or in the future) to their harassment.
A large number of people are running around going "If your chromosomes are XY, you are a man". This is false - a wide range of variations can result in people having atypical chromosomes and their bodies still being female, or predominantly feminized.
