" As trans*, birth gender does not reconcile with gender identity. Addressing this disconnect is the trans* experience....In your example your friends appear to be F who have chosen to present as non binary so their gender is not non binary as they still identify as F. They are simply F who like to play with their presentation."
I must have missed that memo. I don't see people being born with gender. I see gender as a social construct which helps society differentiate between male and female. As for my friends, you are wrong. Being an inquisitive type, I inquired deeply into just what this meant, (this non-binary/androgynous presentation). I was clearly told that this was who/how they identified and it was who they were. Because we are friends, I was able to explore more deeply and they were clear to me that their sexual orientation, (the people that they were attracted to sexually), was "all of the above, M/F/whatever.
So yes we come from different schools of thought. I believe that we are all born male or female, (or in an infinitesimally tiny minority, intersex or sexually ambiguous.) I think that from that moment of birth we are taught/conditioned to behave in that manner deemed appropriate to our sex at birth.
In the case of the transsexual, for reasons yet to be fully understood, that conditioning runs contrary to the innate sexual identity of that child, resulting in that desperate dysphoria which usually ends in either a full medical transformation or death.
In the case of the transgendered or trans* individuals, the results are as myriad as the nuanced colors on a spectrum.
"Gender identity is unique to an individual. Their appearance may be gendered and may provide a clue as to their gender identity and may be consistent with their birth gender or it may not, and gender identity is more than a simple classification as F or M."
Again...you are speaking about social construct, a fungible choice, or maybe even a paraphilia, I don't know as I am certainly no expert in trans* culture or experience. Nevertheless I do understand what it means to be born with the wrong sexual characteristics, (genitals), and I can assure you that that is NOT a good thing or a pleasant experience. But...it can be remedied and the sooner the better.