(Response to the gender headcannons) None of these headcannons are correct. The reason why Kirito ended up with that avatar design in GGO is because it's actually a rare type known as [M9000], given to him due to his many logged in-game hours. That's it.

I’m pretty sure “headcanon” is also used to refer to things that contradict canon sometimes? But anyway, the FTM confession didn’t actually say anything about the model, just his reaction.

If we are going into that subject though, I believe the neuro-sex confession isn’t that far off regarding how the Amusphere works, actually? While I am pretty sure he did get that avatar by chance (I don’t actually remember anything about the logged in-game hours thing you mentioned, but that might just be bad memory from my part), Volume 5 does mention the brain scan takes in consideration something akin to “neuro-sex”:

The recent VR games, for almost all of the titles, forbid changing the sex of the player and avatar. The reason is because the long-term use of an avatar of the opposite sex results in adverse effects for the spirit and body that cannot be ignored. However, I have heard that, because the identification of the players’ sex occurs due to the players’ brain waves, in extremely rare cases, due to some impulse the system decides with the opposite sex, players have been startled when they dive in.

- Sword Art Online Volume 5 (Page 116 from the fan translation)

So, I don’t know, I think saying those headcanons are “not correct” sounds a bit much, at least for me. I think it’s neat to see people wondering about the technology and characters in SAO!

- Mod Fil