Never expected a Heinlein reference on this site, but perhaps I should have considering his work is full of incest harems.
Hehe well I read the Heinlein short story long long ago, I was a young adult at the time (I'm near 50 yo) but I own a precious DVD copy of Predestination, a very underrated movie imho, maybe because it was made in Australia and is out of the box of what usually "Hollywood" does. Even knowing that all the key plot characters in the movie are all the same character I still got a great reaction on how it was adapted to cinema.
Well it is not totally correct to say "full of incest harems" it is just the "perfect" paradox, the main character whoever it is, is "his" own mother and father, its the "hero" and the "villain" etc etc its very complex but it is the full "perfect" circle. Makes us think on the old saying "what came first, the egg or the chicken?", well we have that saying in Portuguese, not really sure if there is a similar one in English.