Earlier quoted context omitted.
That brings up the question of what one means by "sex". As I understand it, sex is primarily about the kinds of gametes one produces - either large gametes (female) or small gametes (male). The genetic implementation of that is in some sense a secondary detail, since it varies between organisms. Reptiles, for instance, only have XX chromosomes and sex is determined by environment (or something like that). I would exp…
No, they're isogamous and have no sexes. They do have mating types.
Ah, that makes sense as well. But the idea of thousands of sexes seemed suspect to me.