Based on an analysis of the Spanish census and the January 1, 2005 municipal register and on exploratory fieldwork in Catalonia, this paper combines ethnography and demography, in conjunction with current Spanish reunification law, to examine the dynamics of what appears to be high fertility among Gambian immigrants living in Spain. We suggest that this high fertility rate reflects several things. One is the high costs of living in Spain for an unskilled, often-undocumented, but also relatively-longstanding SubSaharan group from a homeland with high rates of fertility: a homeland with which close ties remain vital for migrants in highly marginal conditions. Another is the replacement, in some cases, of older wives by younger ones from Africa, resulting in high rates of reproduction for short slices of time by a circulating pool of young women. We focus, however, on the role of Spanish and European policies themselves in shaping these numbers, particularly those policies that place restrictions on the free movement of people. We conclude that the most interesting demographic facet of this population may not be high fertility but rather the paradoxical dynamics of child accumulation in particular geographic regions as an artifact of Spanish law itself.