Where income is higher, life spans are longer. As incomes have diverged between this country’s richest and poorest counties, so have the life expectancies of their residents. Annie Lowry in the New York Times has authored “Income Gap, Meet the Longevity Gap,” in which she details stark differences in lifespan in otherwise matched locales, differentiated primarily by their wealth.

But beyond length of life, quality of life is also profoundly affected by poverty. Health disparities are literally built into developing brains of society’s youngest and most vulnerable members, ages birth to three, and the implications can last a lifetime.

Extensive research on the biology of stress repeatedly demonstrates that healthy development can be derailed by excessive or prolonged activation of stress response systems in the body (especially the brain), with damaging effects on learning, behavior, and health across the lifespan. Poverty confers toxic stress on children and their families.

Lives so affected are lives in catch-up for perpetuity. As a humane society, the costs are incalcuable. Gross income inequality and poverty represent failures of not only public policy, but of empathy. We can do better. We must do better.