http://www.theatlantic.com/health/archive/2015/04/genes-dont-cause-racial-health-disparities-society-does/389637/

Even if scientists could get ancestry right, and pry it apart from society’s tightly held beliefs about race, it still wouldn’t account for enough disease to explain health disparities. “If you look at overall health disparities across the board,” Kittles said, “the bulk of those disparities are not due to any biological difference. The vast majority of health disparities are due to social, behavioral, and environmental components.”

Why hasn’t attention turned, then, to social inequality, not genetics, as the source of health disparities? The main reason is the political ramification. “If you show that this is a predisposition that is genetically determined—black people just have this gene, there’s nothing we can do about it, this is just nature—then society is completely absolved. We don’t have any responsibility to solve this problem,” Kaufman said. “If you show that it is because of racism and injustice and people’s living conditions, well, then, there is some responsibility and we have to do something about this.”

In his book Making the Mexican Diabetic: Race, Science, and Inequality, Michael Montoya shows how epidemiologists try to explain diabetes through genetics, even if evidence points in a social direction: lifestyle disruptions, dispossession, and poverty, which disproportionately affect minorities. “It is much easier to say it must be something [wrong] with those people than it is [to say something’s wrong] with the way we have arranged our society,” Montoya told me.