STILL READING!!!
* SPOILERS TO AVOID FOR ANYONE WHO HASN'T READ
INVERSIONS!!! *
It's pretty obvious the Doctor is Culture from the beginning (if you're told
Inversions is a Culture novel. I wonder now how my impressions would have differed had I not known). I suspected the bodyguard was as well, but when he started telling the little son of the Protector the stories of the two friends in the faraway fairy-tale land, I was pretty certain. (I'm assuming I'm not totally wrong; that's how things seem where I am at the moment: the Doctor & narrator have just returned with the royal party from the Circuition [or whatever it's called] to the provinces.) My guess at the moment is that the Doctor and bodyguard are the two estranged friends, one in favor of and one opposed to Culture interference in unContacted civilizations. (Not sure if this is what you meant by it being all about.

)
The glanding stuff is a neat idea. So is the diagnostic "control panel" visualization method Banks described. (Remember, the way a person begins the "gender reassignment" is to visualize accessing a picture of themself and changing it from male to female or vice versa.) But the switching sex idea didn't seem all that new, maybe since I read Varley's lunar civ stories a good while back. (Still remember the one about the environmental artist woman who has sex with a male clone of herself that has somehow escaped disposal when she became a woman again.

) [One good thing to remember about Varley BESIDES his writing: he was once rude to Hyppo at a convention or something and she has never forgiven him and still bitches about it even now YEARS LATER. Not that anyone else would blame him: having ugly women throw themselves at you probably gets old after a while!] The original part of the idea with Banks, though, was the WAY people switch, by just visualizing it AND then their bodies starting the change.
Anyway, Secher, have you read the short story
The State of the Art in the collection by the same name? A Contact ship finds and observes Earth. It also touches on the Culture-internal conflict of to Contact or not to Contact....

(Also features the woman Sma and drone from
Use of Weapons.)
"Let the dead give water to the dead. As for me, it's NO MORE FUCKING TEARS!"