First off, references to human cloning in Poul Anderson's sf. Second off, a reference to human cloning in sf in mainstream fiction. Third off, Brian Aldiss's succinct comparison of mainstream with sf.
In Anderson's Psychotechnic History, the Un-Men are clones of Stefan Rostomily. In his Technic History, Duke Edwin Cairncross plans to clone himself when he has usurped the Imperial Throne.
"'...as far as I know cloning exists only in the pages of science fiction."
-Susan Howatch, Mystical Paths (London, 1996), PART TWO, TWO, I, pp. 358-359.
Thus, Howatch's character refers obliquely to works like Anderson's future histories.
"The virtue of sf is that it presents man in relation to his surroundings: man on another planet, man in a different era, man faced with alien life, man against one of his own inventions. Without making too large a claim for it, we may say that sf is the only way of dealing with ourselves as an organic part of the universe; whereas the ordinary novel can only portray us as a part of human society. This is the justification of the term 'science-fiction' - not, perhaps, as hideous a term as it seems."
-Brian Aldiss, Space, Time And Nathaniel (London, 1966), INTRODUCTION, p. 11.
"Mankind as an organic part of the universe" is a sound description of Poul Anderson's works.
Also appropriate is the concluding phrase of the concluding story in STAN:
"...a voice singing in a new universe."
-Brian Aldiss, "Dumb Show" IN Space, Time And Nathaniel, pp. 153-159 AT p. 159.