Doesn't all this become much simpler (though still some areas of complexity) as long as we are clear on the difference between sex and gender. Women's world cup is based on sex, so doesn't matter if you gender identify as a man, woman, cat, your sex determines whether you are eligible.
Complexity is still there when people have changed sex (hormones, operations etc), but it's a much smaller amount of complexity.
I am sure the above gets me on the naughty step.