Factoring in 5-7% annual return on investment, it's only about 25-30k per year, not 50k. (Given P(0) = 0 and P(n) = P(n-1) * 1.07 + $25,000, P(20) would be $1,024,887.31.) Perhaps still a bit high, but not too far off, especially considering that the second child probably has a lower marginal cost than the first.