Arguably the Pygmalion effect might serve children well here. The parents expect IQ 130 children; their IQ 115 children are persuaded to learn calculus, though perhaps with a bit of extra difficulty.
Two parents with an IQ of 130 can expect about 6 children before one scores higher than they do.
Caveat: In reality, the number of children required may be a little lower, due to family history. Regression to the mean regresses toward family mean, not overall population mean.