The only thing I can think of is the chemical castration that is done to sex offenders or to treat cancer, but for the most part, this is done to adults, and not children.
Or are you referring to something else that would affect children of both sexes?
They are also factually incorrect as surgical intervention is not and has never been part of the recommended treatment for children. As such their intentions are either misinformed or malicious.
You are wrong. Surgical interventions are performed for children by reputable hospitals and surgeons.
This isn't happening.
Intersex children being force-ably sexually re-assigned, that was a thing we did for a long time and which has only barely slowed in recent times. The only sexual modification of children going on is the regularization of the body.