This research project builds on a half-century of demographic studies about turn-of-thetwentieth-century U.S. race differences in fertility. As background, mid-twentieth century demographers began to study historical fertility differentials when a newly released U.S. 1940 Census Bureau report allowed comparisons of aggregated fertility rates by age, race, region and other characteristics for decennial census years 1910 and 1940. They were surprised to find, in 2 back-casting fertility rates, that at some point prior to 1910 the fertility of African American women had dropped, much more precipitously than that of white women. This was surprising because the fertility of very early nineteenth century white and black women stood at biological maximums, although white women had the highest birth rates of all women in North America and perhaps in the world. It was assumed that white women of the time, like most preindustrial women, had high rates because they had not yet elected to practice voluntary fertility control. In contrast, nineteenth century African and African American women experienced high fertility rates under a system of slavery, until the early1860s, with vastly different constraints regarding fertility control to that point. Were white women first to control their fertility? If so, why did African American fertility rates fall far more quickly, once declines began?