As a consequence of increased divorce rates, the proliferation of single-parent families, and patterns of economic stagnation, parents are increasingly relying on extended family to care for children. In the past few decades, a substantial increase in the number of grandparents raising grandchildren has been observed within the United States. Grandparents who raise their grandchildren are particularly vulnerable, as are the grandchildren in their care; however, US policy currently presents many barriers, gaps, and unintended consequences for grandparent caregivers. In this paper, we use two theoretical paradigms 1) structural lag and 2) the political economy of aging perspective to argue that US policy has not kept pace with the reality of the family and–as a result–those families who are most vulnerable often receive the least support. We propose that as family forms become more diverse a redefinition of the family to one that is less bound by residence and biology, to one based more on function, will be required.