A very high IQ child (say 145) an often learn academic material material several times faster than an average IQ one, so it makes sense for him or her to placed with other high IQ children so they can all be taught at an appropriate pace.

Some parents will resent the assertion that their children learn much more slowly than yours. It may well be true, and it does not mean there is anything wrong with their children.

"To see what is in front of one's nose needs a constant struggle." - George Orwell