I'm very curious about gender on The Edge. It's presented in a very binary manner and I have Some Thoughts.
Clearly there is an omniscient narrator and the author can just be like "this is the person's gender and pronouns and you have to believe me" even though any of the characters might not know or be able to "tell" another's gender.
Personally I refuse to believe that among the myriad of utterly insane and fantastic creatures that exist on The Edge, every single one of them has been divided into male and female physiology and matching gender identities. Other cultures must have different ideas of gender. The Woodtrolls and Slaughterers couldn't possibly have the same construct of gender, could they? Nor could every species of goblin and troll.
I think it would have been very interesting to see Twig, especially being so naive and unlearned as he is in the first book, have an understanding of gender as the Woodtrolls would have had, try to assign those genders to the other peoples and creatures he meets, fail horribly at it and have to reevaluate his understanding of gender.