@RadicalAnthro Here's an article about the firefighter who made the initial observations and pushed for the studies... It's an epic story one many levels. This bit being the bit I love the most, good old deductive reasoning!
"Mick had read studies showing women tended to have lower PFAS levels than men, but he didn't know why. One night he couldn't sleep and went down to his shed to change the oil in his wife's car. "That's when I had this light bulb moment," Mick says. "The reason you change the oil in your car is, so you don't blow the engine up. Maybe women have lower PFAS levels because they lose blood when they menstruate? So maybe if firefighters donate blood or plasma, we could get this stuff out of our bodies."
https://www.abc.net.au/news/2022-09-26/mick-tisbury-12-year-fight-to-protect-firefighters/101392332