The book-reading equivalent of watching paint dry is trying to imagine an eugenic thriller based upon a debate among eugenists over when to sterilize a 'defective' child before they can reproduce more 'defectives'.
Sterilize them at birth or age one or age thirteen or even wait till age sixteen ?
Because Eugenics is supposedly about extremely 'fixed' 'unmoving' 'known' hereditary qualities, by definition it is hard to build up a good Moral Panic around it.
Moral Panics need to have a reasonable fear about the seemingly unearthly speed, hiddenness and dynamic fluidity of the social activity it so fears.
But we have all our genes ('defective' or not) from the moment of conception to the moment we dies - so where then is that 'race against time', that much beloved fundamental plot device of the thriller genre ?
Eugenically, proponents of sterilization of the unfit have to admit that it matters not whether the child is 'nipped' at birth or at age thirteen.
But Germ Theory, by contrast, provides a free-floating metaphor from a real world example of a sudden, massive yet invisible and always mutating danger --- a metaphor almost perfectly designed to feed intense Moral Panics.
For nothing is both sudden, massive and yet invisible than a (Germ Theory) pandemic like Europe's Black Death or the global Spanish Flu.
To then say that a Jewish 'bankster' virus has invaded the German soul or that a secret Yellow Peril/Red Commie/Black Power/Brown Wetback plague is ready to take over the American government then has an immediate surface credibility....