We present a novel life-cycle model, grounded in demographic principles, to examine the influence of medical progress, technological progress, and the reduction in age-independent mortality on the rise in life expectancy across socioeconomic groups. Our findings indicate that the expanding disparity in life expectancy across income groups, as well as the growing income inequality among educational groups in the US, can be attributed to a selection process that changes the composition of the initial characteristics (learning ability, schooling effort, and health frailty) of the income groups. This selection process is triggered by the rising income and medical advancements that emerged with the cardiovascular revolution in the 1970s