Oh wow. That’s kinda shitty—
Ahh, so not only are neutral pronouns getting masculine defaults for relation terms (really, it should be sibling, child, spouse, etc), relation terms aren’t ACLed.
This raises the question: how would you ACL those relationship terms? I mean, you have to put something there; otherwise that would flag as suspicious. I suppose showing gender-neutral terms as described above for anyone who doesn’t have the ACL is the obvious solution, but even that could be strange. I can just see: “My profile says you’re my ‘child’, now. What’s up with that?”
Really the ideal seems to be that, for safety, some people shouldn’t know you’ve set a custom gender.
So the real solution here is to allow a user to set multiple custom genders, each with a separate ACL list. So you can have a public / family view gender, and then a ‘for friends I’m out to’ gender, at a minimum.
In the meantime, signal boost, because this is going to be non-obvious to a whole lot of people and doesn’t seem to be documented anywhere.