James Watson, who elucidated the structure of DNA 50 years ago with Francis Crick, has published an opinion advocating the use of gene therapy to eliminate stupidity. This has generated sharp criticism relating to the technological as well as ethical feasability. To date, we do not know enough about the myriad of genes that affect intelligence, and there is also a great amount of environmental factors. Even if we did, people argue improving intelligence by genetic manipulation is not ethically acceptable.
http://www.newscientist.com/news/news.jsp?id=ns99993451
Personally I would love to see this happen. We'd be alot better off if everyone was smarter. Nature gave us the intelligence to unlock its secrets and alter them. It seems hypocritical to propose eliminating disease by gene therapy, but not to go one step further and improve things.