Don’t forget the 1979 mid-season replacement:"Turnabout Intruder" is just a hacked-together rip-off of Thorne Smith's novel Turnabout or the 1940 film on which it was based, in which a husband and wife temporarily swap bodies and in the end decide that things work best if they stick to the traditional gender roles.
https://en.wikipedia.org/wiki/Turnabout_(film)
We fans are collectively far more concerned with the continuity implications relative to TOS as a whole than SInger or Roddenberry were.

As I said, don’t forget, because nearly everyone else has.
Incidentally, this Turnabout is canon: in the unaired eighth episode, John Schuck is transmogrified with a 23rd century Klingon ambassador.
