[rdinkel]

> Sorry, the author makes a good argument that there are only two sexes if and only if you define sex by the specific definition of gametes.

This definition of sex is fundamental. It's the only one that applies across all sexually-reproducing species.

> They are getting up in arms because they don't like it that the expression of sex phenotypes is heterogenous, overlapping, and scary, and that makes their small minds feel funny.

They probably just disagree with the bizarre and false claim, made so often in recent years for reasons of ideology rather than fact, that humans can change sex and that there are medical interventions that supposedly make this possible.