They've done quite a number of studies like that, including studies on identical twins adopted by different parents, which gives you matching DNA.
The reason scientists aren't saying such things, is because it's pretty clearly wrong.
Heres a wikipedia page on it:
You can't judge evidence based on a popularity contest.
You can find some in the link he supplied https://en.wikipedia.org/wiki/Ashkenazi_Jewish_intelligence#...
40 - 54 - Severely challenged
55 - 69 - Challenged (2.3% of test takers)
70 - 84 - Below average
85 - 114 - Average (68% of test takers)
115 - 129 - Above average
130 - 144 - Gifted (2.3% of test takers)
145 - 159 - Genius (Less than 1% of test takers)
160 - 175 - Extraordinary genius
http://www.free-iqtest.net/iq-score-guide.asp
From the wikipedia article, Ashkenazi Jews have an average IQs - a few points higher than American, Hongkong national average.
Scientists, like every members of society, are bound by social rules. Some taboo cannot be broken, and when they are its a career ending move. It’s easier to get founding by inventing 126 genders that don’t exist than saying a few obvious truths, that are backed by science.