Exactly how steamy is this story?
Theoretical G
The sex in Childhood's End has all the steaminess of a biology class taught by a professor who only has a passing, theoretical knowledge of the horizontal pastime. Case in point:
In particular, the patterns of sexual mores—insofar as there had ever been one pattern—had altered radically. It had been virtually shattered by two inventions, which were, ironically enough, of purely human origin and owed nothing to the Overlords.
The first was a completely reliable oral contraceptive: the second was an equally infallible method […] of identifying the father of any child. (6.24-25)
Other than a few gentlemen noticing a pretty lady, the characters and narrator are too busy focusing on the big picture to wonder or worry about what's going on behind closed doors. In which case, there's little need for us to either.