With genes it is complicated. Sometimes one gene encodes one trait. But often dozen genes cooperate on one trait, and one gene contributes to dozen traits. And most often, we don't know exactly, either because our knowledge is poor, or the terittory is very complicated.
So if there would be a political pressure for "criminal gene" elimination, it could easily translate to a law of elimination some specific gene XYZ123, which according to one (low p-value, never replicated) study increases criminality by 1% (although only in presence of genes ABC987 and MN45, and only if given individual has a diabetes and was born in Sagittarius constellation) and also increases creativity by 2% (in presence of gene PQR654, and if the individual's mother drank wine daily during pregnancy). For the lack of better candidates, this gene would be declared The Criminal Gene, and the 15% of people who have it would be sterilized when they commit a felony (and 5% of them would be exonerated later because some mistake during the trial would be discovered).
In absence of the reliable science (which means: until we are able to engineer it genetically), the "objective" laws would be guesses, based mostly on political pressure.
Also, would you like to break this taboo and allow your opponents to use sterilization to achieve their goals too? (Imagine that one day feminists would get enough power, and decide that the only way to get rid of the evil patriarchy forever is to sterilize all the white able hetero cis males. If you protest, you are the first to go to sterilization.) Sometimes it is good to have taboos.
Related: The Blank Slate, The Psychological Diversity of Mankind, Admitting to Bias
"Hjernevask" a well known (in Norway at least) documentary series that I am sure will be interesting to rationalists here is now available with English subtitles online. Produced by Ole Martin Ihle and Harald Eia a Norwegian documentarian and comedian, it casts a light on both ways in which we know people to be different as well as the culture that is academia in the Nordic country and probably elsewhere as well.
The Series
The link go to the YouTube videos with English subtitles. Because linkrot sucks I'm providing another source for the videos.
Some Commentary
There was very little in the series that I found new and disagreed with some presentations. But this is not surprising given my eccentric interest in humans. (^_^) I found the interviews with the scientists and academics interesting and think that overall the series presents a good overview something well worth watching especially considering some of the debates I've seen taken place here recently. (;_;)
The latter wrote that in a 2010 article on the documentary series that I would also recommend reading. HT to iSteve where it is quoted in full.