Isn't this just the plot of Gattaca?
or something fairly similar.
Personally I don't think there's any excuse for stupidity. If you have a genuine mental disability, fair enough. But there are a lot of people of average or above average intelligence who have a sort of wilful stupidity, a refusal to learn and are proud of this.
Sort them out first*, which is a social problem rather than a scientific or genetic one, and then maybe we can talk about artificially increasing intelligence. I would also like to see a mechanism for how this works before I believe that you're not totally talking out of your arse as well.

*Encouraging (and enforcing if needs be) learning (of some kind, not everyone is academic) from a very young age, and if that doesn't work, flamethrower the lot of 'em.
(berk, Fri 14 Jan 2011, 12:04, 2 replies, latest was 15 years ago)

Gattaca was more about genetic engineering and selection.

(PsychoChomp, Fri 14 Jan 2011, 12:08, Reply)

it's nothing like the plot of Gattaca

( Vipros. clever got me this far, then tricky got me in, Fri 14 Jan 2011, 12:14, Reply)