Reader’s note:
When discussing the sex class of human people, this is only decided by a person having a body formed around the production of one gamete or the other, regardless of the production status of those gametes.
It is this basis, as per the Supreme Court clarification of the EA2010, that allows legitimate discrimination for the provision of single sex services and facilities.
This is not a ‘belief’ this is an established scientific fact that serves as the foundation of many aspects of life. Including the law.