speaking of that collaborative Ferengi gender headcanon
I think a reasonable way for a single sexed society to develop the idea of coercive gendering would be if their pregnancies are unusually difficult or unpleasant for them, enough so for it to have been difficult for them, at some point in the past, to keep their population up without controlling people’s reproductive decisions
“look, if you don’t have babies we’re all gonna die, sorry, we drew straws and your life is not your own anymore, in a few generations we’ll have come up with a nice system to decide this for us and essentialized it”
of course now that they’ve got pretty great medical technology pregnancy is a lot easier and fewer parents die, but the gender system hasn’t been explicitly about that for thousands of years, it has its own cultural inertia now
I know I had a write-up in my notes before my old computer kicked it about Ferengi pregnancies, and how births are rather awful despite their…elasticity because look at the size of their skulls.
[I love the ‘collaborative Ferengi gender headcanon’ btw]