Gender identity... is the same as the furry fetish? I have to disagree there. While most furries will consider their fursona as part of their identity, it's totally seperate from their gender identity.
Gender identity is the gender you associate yourself with, mentally, physically and emotionally. Your fursona is the animal you assicoate yourself with, which is a totally different species. And yes you may feel stronly about it, but there's a reason we don't have fursuits as an option alongside formal wear.
I personally have a friend in real life who is otherkin, he's actually the partner of the owner of Bad Dragon. I think I'll pick his brains on this subject now to get a clearer view.
And if you can suggest that skirts are merely costume, then the same can be said about trousers. Skirts express femininity, and trousers express masculinity. Both can be considered costume.
Well damn, Red beat me to it really. Uhm... Not much more I can really think to add on at the moment in this state of mind, other than the psych terms she is using is pretty much right. So yeah, Way to ninja me, Red~