The vast majority of people are also born with greatly altered glands housed within their central nervous systems, usually referred to as 'drug glands'. These secrete - on command - mood- and sensory-appreciation-altering compounds into the person's bloodstream. A similar preponderance of Culture inhabitants have subtly altered reproductive organs - and control over the associated nerves - to enhance sexual pleasure. Ovulation is at will in the female, and a fetus up to a certain stage may be re-absorbed, aborted, or held at a static point in its development; again, as willed. An elaborate thought-code, self-administered in a trance-like state (or simply a consistent desire, even if not conscious) will lead, over the course of about a year, to what amounts to a viral change from one sex into the other. The convention - tradition, even - in the Culture during the time of the stories written so far is that each person should give birth to one child in their lives. In practice, the population grows slowly. (And sporadically, in addition, for other reasons, as we'll come to later.)
From Iain M. Banks' A Few Notes on the Culture, about his Culture setting/series of novels. The Culture is a radically postscarcity anarcho-communist civilization living primarily on AI supervised spaceships and space habitats. I would recommend starting with Player of Games or Surface Detail.
people would be pressing that theoretical button just to see if it works
Yes, of course. That's right, comrade, there is no genderswap button, and it most certainly will not be pushed to all iOS, Android, and Windows devices by the end of the year. 😉
