Kinship has often been referred to as the heart of anthropology because societies are woven together by genealogical ties. In this paper we present a general model of the effect of the tradition of marriage on the potential number of individuals that can be identified as kin. The exact amount of increase in the number identifiable kin depends on demographic variables, but it will always be greater than the mere doubling of kin that might be first assumed. It is our hope that this model will stimulate discussions over whether or not such an increase in identified kin might have been important to human evolution, and if so, in what way and under what circumstances. Such discussions may help bridge the gap that has been created between those anthropologists who see kinship as fundamentally biological and those who see it as a purely cultural phenomenon.