Nothing "solves" the demarcation problem. But we can come up with something a bit more reasonable than the M/F binary. > And I can see arguments for self iden

Nothing "solves" the demarcation problem. But we can come up with something a bit more reasonable than the M/F binary. > And I can see arguments for self identification for almost all passport fields. This isn't relevant. The desire for self-identification is not a sufficient reason to let people change fields on their passport in the first place. Think of it more like hair color. You can dye your hair any color you like, or shave your head, and your passport will simply reflect what hair color you happen to have. It's not necessary to know what hair color someone was born with. People can self-determine their hair color, but all that really means is that they can dye it, or if your hair is in the middle between blond and brown, you can write down either option (your choice).