More hyperbole.
'exceptionally primitive understanding of the biology of sex development' seems to now be the description of understanding that well established science has shown that a female person is a person with the body formed around the production of large gametes, regardless of whether this production is happening, has happened or will happen.
There is no third sex. No human has produced both gametes. And with modern techniques it is possible to categorise every human on this planet using a series of parameters. Still no third sex, either as a stand alone sex or an 'inbetween' sex.
Posters who are trying to present a case that there is anything other than this as a categorisation, really should start to produce some evidence. Because if there is anything other than this, that is indeed a world changing discovery.
There is no understanding of the biology of sex development other than this, except for those which are based in philosophical theories and beliefs and obviously without evidence, since you have yet to link any up.