"child genius" is a correct and usable phrase in written English.
For example, "My five year old son amazed me with how quickly he was able to understand complicated concepts - he's definitely a child genius!".
I wasn't some kind of antisocial child genius.
He had already seen eight years' service as a child genius. . . .
But there is no such allusion in, for example, Channel 4's show Child Genius.
Other character genres include the child genius, the superhero, the fairy tale princess and the loner.
Freeman was a child genius, being a Quiz Kid on the radio in the 1940s.
He's a child genius turned mob accountant who uncovers a conspiracy.
A child-genius is a challenging thing for an author to create, and I'm not convinced.
Ruby herself is an odd mixture of likeable sauciness and child-genius stereotype.
How else are they ever going to compete in child-genius competitions, or stand up in front of a live audience to demonstrate how well they've memorised the London Underground map?
This is sort of that, except instead of being a scuba diver it's a Labour activist at a music festival taking a selfie with her husband, and instead of a shark it's the broken former leader of the country staring deeply into the lens of the camera with the blunt boredom of a child-genius trying to enjoy Shrek the Third.
