Should produce... given what definition? I thought gamete size was definitive?

Look, I get what you're saying. Such cases aren't "normal". The claim that "humans have two biological sexes" is true in same way as the claim "humans have five fingers." And yet, people with six fingers exist, as do uncommon sex variations. It's fine. It happens.

The only reason to insist so stridently that there's an absolute and inevitable binary is if you're trying to enforce a social or religious norm, and are insisting that it's an immutable fact about the world instead of something culturally mediated.