According to the OED, word salad from 1895, and from either the french (salade de mots) or the german (Wortsalat). Which frankly makes me think of coleslaw, and lots of cabbage.............
Word salad pretty common in these parts, with or without mayonnaise (or cabbage)................
As regards biology and all that, it is relatively simple to go all sci-fi and think of alternatives to our binary sex system -- Mary Gentle, 'Golden Witchbreed', where individuals are not born either male or female, it is not predetermined, but they become either male or female at 'puberty'. Those that don't and remain neuter are a bit special and die early as I recall. Then we have Ursula LeGuin (Left Hand of Darkness), where individuals only become sexed (and may be either) during special times. In both cases, you could imagine a process whereby individuals could alter or transform their sex, in effect, because in these cases it is obvious that each individual contains the genetic information for both sexes. Although in the Witchbreed case, you would have the same issue as with our species, that you cannot totally undo development as one sex. So, once an organ has developed into a penis, for example, hard to see how biology could undo that, and shrink it into a clitoris. Just because development could be branched, doesn't mean that you could go backwards and take the other one instead! The other leg of the trousers of sex cannot be reached.................
The only situation I can see where it might work from a sci-fi point of view is where you had a species that (like some fish), individuals can change sex as they get larger. So, you could imagine small fish being male and staying male, or others being rushed through the male stages and ending up female. But again, difficult to see how a big female fish-person could go backwards and become and stay a male fish-person, at best they'd be an unusually large male fish-person, with possibly ambiguous genitalia/gonads depending on how exactly the biology of the sequential sex worked.............
The only one where it would work is Ursulas, but then you'd still have people being just people most of the time (the point of the whole concept), and then only being male or only female when in heat (I think she discussed this -- and our protagonist, being from earth, was seen as a 'pervert' not because he was just and only ever male, but because he was always sexed!).
And none of these fit with actual human biology and our binary sex -- which is kind of the whole point of creating these sci-fi scenarios. Of course, also probably not a coincidence that these scenarios were created by women writers! (or maybe I just tend to read the ones written by women?).
Whatever nonsense the TRAs are coming out with, it ain't even interesting sci-fi....................