I forgot about that:
Take height. Though health and nutrition can affect stature, height is highly heritable: no one thinks that Kareem Abdul-Jabbar just ate more Wheaties growing up than Danny DeVito. Height should therefore be a target-rich area in the search for genes, and in 2007 a genomewide scan of nearly 16,000 people turned up a dozen of them. But these genes collectively accounted for just 2 percent of the variation in height, and a person who had most of the genes was barely an inch taller, on average, than a person who had few of them. If that’s the best we can do for height, which can be assessed with a tape measure, what can we expect for more elusive traits like intelligence or personality?
From Steven Pinker in http://www.nytimes.com/2009/01/11/magazine/11Genome-t.html
Yes, that's all people claim, and I believe even this 2% claim failed to replicate.
If it's worth saying, but not worth its own post, even in Discussion, it goes here.