Developed in Britain and the United States in the 1980s, genetic profiling has since become a global technology. Today, it is widely regarded as the evidentiary “gold standard” in individual and forensic identification. However, its origins as a technology of post-empire at Britain’s externalized borders in South Asia have remained unexamined. This article will argue that the first state-sanctioned use of “DNA fingerprints,” a pilot program exploring its value in disputed cases of family reunification migration from Bangladesh and Pakistan to Britain’s postcolonial cities, repays closer examination. National and transnational responses to the advent of genetic profiling as an identification technology demonstrate the interplay between imperial and postcolonial models and networks of power and truth production. At the same time, this experiment prefigured and conditioned the wider reception of DNA profiling in matters of kinship. Far from being a footnote, the use of genetic profiling by migrants determined to exercise their legal rights in the face of a hostile state also worked to naturalize genetic ties as the markers of “true” familial relationships.