> "humans have two biological sexes" is true in same way as the claim "humans have five fingers."
No. There are no intermediates. Nobody produces "spergs" or "speggs". Someone may produce no gametes because they're not yet mature or because of a developmental disorder, but that just means that they will later on in life, or won't produce the gametes their body is set up to produce.
> The only reason
Bullshit. I bring this up because it's a fundamental fact of biology and HN should know better than to push pseudoscience. Sex in humans is binary and immutable, but that doesn't mean boys can't play with dolls and girls can't like trucks or whatever dumb culture war stuff is raging.