There's been a lot of talk recently about whether race is still a relevant concept in the US (see recent supreme court ruling against affirmative action: I'm not an expert in educational policy, but I can tell you that it fundamentally still matters when one looks at health outcomes. A recent University of Illinois study has documented a long known (and depressingly persistent) epidemiological fact: in the US black college educated mothers have significantly higher rates of infant mortality rate than white mothers. The difference can almost wholly be attributed to a higher rate of premature births among black mothers, though this trend only holds truth when you look at black mothers born in the US, rather than more recent immigrants. All this points to the hypothesis that it is partly the experience of growing up black in America, the subtle and more overt experiences of racism and discrimination day after day, year after year which leads to higher stress levels which then influence the rate of premature birth. These are hypotheses and correlations, rather than causations, but depressing nonetheless. Race may be socially constructed, but in this setting (and others too) it's remains a highly relevant social fact. Pretending it doesn't matter won't help us fix these disparities and inequalities.