If you're not a black person, suppose you were. Suppose you were also born in New Orleans' Lower Ninth Ward, which was already in poverty before it was devastated by Hurricane Katrina. So you sought to better your life by getting a job in Chicago. But then US government officials forced you not to take the job, because DNA tests proved that you are not closely related to any white person.
If we'd had DNA tests back in 1850, this would have been perfectly acceptable to many Americans of the time, perhaps even to my white ancestors. Today we recognize that this would be a jaw-dropping violation of your human rights. We wouldn't contemplate doing this; we're better than that.
Now suppose you were born in Somalia, where gruesome disease and incomprehensible violence threatened you and your family. And to escape that and work hard to better your life, you wanted to get a job in Chicago. But the US government informed you that you cannot, because DNA tests prove that you are not closely related to anyone who lives in America. Could this happen?
It is already happening. US consular officers now have the authority to require DNA tests of potential migrants, and many do (pdf). The United Kingdom does this as well. France briefly considered doing the same last year, but shelved the plan after public outcry. Now the Wall Street Journal reports that the US government is even considering doing the same for desperate refugees from war-ravaged lands like Somalia and Côte d'Ivoire. (Here is an ungated version; read the last sentence.)
Most Somalians did not choose to be Somalian any more than you chose your gender or ethnicity. Why are we as Americans not outraged that our government would contemplate denying people, especially desperate refugees, the opportunity to work in this country based on what their DNA says about who their relatives are? This has nothing to do with how productive they are as workers, any more than what your DNA says about your gender or ethnicity determines your productivity in your work. Denying access to a job because of any information in your DNA that doesn't affect your ability to do the job is labor market discrimination.
As a nation we have apparently decided that some forms of discrimination are acceptable, while others are barbaric. Legal scholar Howard Chang of the University of Pennsylvania has some sharp thoughts (pdf) on this subject. My co-authors and I have an economic take.