4 ideas
In an alternate 1976 England with no Reformation, ten-year-old Hubert Anvil, a chorister at Coverley, has a voice so extraordinary that Church authorities decide he should be castrated to preserve it, and his father consents. A medical emergency then brings about the loss anyway, so the decision about his body is taken from him before he can make it himself.
An authority that claims to serve a higher good, such as God's glory expressed through sacred music, can present the mutilation of a person as an honor. Because the art is sincerely valued, the harm to the individual gets reframed as a privilege, and objections become impiety rather than protection.
Parents and institutions claim the right to make irreversible bodily decisions for a child in his supposed long-term interest. The child cannot yet weigh what he would lose, such as adult sexuality or an ordinary future, so the adults who decide are weighing their own interests and values instead. The child's own resistance, running away, is his only available veto.
Altering one historical pivot, the Reformation, produces a world where Church control of science, technology, and personal life seems normal to its inhabitants. Characters in that world even read a banned novel imagining our history as fantasy. The lens makes the reader treat their own world's arrangements as equally contingent rather than inevitable.