Bad idea. It reminds of Mencken's proposal, which (updated by me) essentially amounted to this: The kind of person who would refrain from having children to get a prize of a blinged-out Escalade and two gold incisor implants is probably the kind of person we don't want contributing to our gene pool anyway. Except Mencken's proposal would weed out the stupid and decrease their percentage of the population, whereas yours would weed out the intelligent and far-seeing -- a terrible outcome.