There's a girl in our pre-K program who is tall, smart, and will turn six over the summer. This means that she'll be seven at the end of her kindergarten year. That isn't so amazingly unusual (I have one like that), but it is too bad because she doesn't need to be held back. The reason she's still in pre-K is because she has a twin brother who was recommended for a second year of the program and her parents didn't want to split them up.
I saw her drawing and writing, and it's clear she's already able to handle what would have been her kindergarten year. Clearly, at this rate she's just going to continue to shine and leave her brother in the dust. Since it's obvious that we can't improve the little fellow's mind, in order to narrow the gap I think we need to embark on a serious regimen of tearing down the girl's self-esteem.
The teachers should be pointing out how her work sets her apart from the others, how her age gives her an unfair advantage, how her young peers resent her successes. This won't reduce her intelligence, of course, but it should block any further advances in achievement. Then the brother won't have to worry about being compared to his much more able sister, and soon they'll both be coasting along at a nice level of acceptable mediocrity.
Just a modest proposal.