That’s a great idea.
I did some digging and I basically found 3 models:
- many pre-defined gender-options (e.g. some dating sites).
I haven’t created an account on any of these sites to look further into this. Also I think this is the worst option. - Genders as instances created by the community (e.g. Wikidata).
On Wikidata you can basically create an item for any gender (as long as it meets the notability policy), but making it available as an option for gender seems to need community consensus. E.g. Angel Haze has 3 references stating that she is agender, but changing her gender from non-binary to agender is not possible because it’s not an accepted value for gender (btw it’s called sex and gender on Wikidata because it’s used for animals too I guess). - Free text only (e.g. Wikipedia, Mastodon).
Wikipedia doesn’t categorize people by pre-defined genders, but simply makes it clear in the text (use of pronouns or mentions of the gender the person identifies as). On mastodon you can define up to 4 labels for yourself and enter any value for the label and the content.
Option 2 is a lot of work, very slow and I don’t really get the point of why other people have to approve of the use of any gender. So I prefer the free text option.
PS: To show that this is not just a theoretical issue I created a collection of artists on MB that are mislabeled or not labeled at all because the correct gender doesn’t exist in MB.