I assume it was an attempt to define a woman by some biological means in order to exclude trans athletes from competition.
It's a shame, but it ruins women's swimming to have Lia Thomas winning. The other competitors also have "rights". They shouldn't be competing with a 6 feet 4 inches person with a penis who calls himself a woman, who was an average swimmer in men's swimming a short while ago..
I don't know how you do it. I assume menstruation was an attempt.