"Arline Geronimus, a professor at the University of Michigan School of Public Health, calls this phenomenon “weathering.” She theorizes that the cumulative impact of constantly dealing with disadvantages causes birth outcomes for black women to deteriorate with maternal age. “Women in particular, especially in low-income communities, have enormous stressors they’re coping with,” she says. “They’re usually centrally responsible for raising children, taking care of ailing elders, working, earning money, dealing with material hardship.” And it’s not just hardships associated with poverty. Geronimus says that for middle- and upper-class blacks, the pressure to be model minorities — or sometimes being the only minority — can also take a toll. When Geronimus began talking about her weathering theory more than 20 years ago, she was widely pilloried. Some called her racist; others wanted her fired. But in the years since, there’s been growing acceptance of her view that constant stress does lead to the deterioration of bodily systems: the cardiovascular system, the metabolic system and the immune system."