Science fiction and sex

When a novel begins with the words, "The penis will be obsolete in five years," , one gets the idea that the interaction of sex and science fiction can be far more creative than pulp novels with scantily clad victims in the clutches of tentacled horrors.

Sexual concepts entered science fiction before the sexual revolution. Among the first, in 1935, was Olaf Stapledon with his novel Odd John. "It would be a stretch to say Farmer invented sexual science fiction (especially considering some of the people on this very list predate him), but he did shatter the mainstream notion that sex had no place in science fiction. His 1953 short story "The Lovers" was an overnight sensation for its sophisticated, intelligent depiction of love between a human and an alien, which he followed up with five more stories in a similar vein in his 1960 anthology Strange Relations.

Incest and its relatives

Stapledon suggested that his advanced protagonist may have had a relationship with his mundane mother. Eventually, he concludes that relationships with normal humans would be too much like bestiality.

E.E. "Doc" Smith's Lensman series has no explicit sex, but notes and conversations indicate that he may have had an unpublishable sequel to Children of the Lens in mind, for which sibling mating would be logical.