In this paper, I will examine Home Office surveillance of young West Indians and South Asians who traveled to Britain to be reunited with their families. Officials drew on racial discourses to discount these young people’s claims to entry to the United Kingdom by calling into question both their family connections and their age. In the case of both Afro-Caribbeans and South Asians, officials dismissed the sincerity of family ties, particularly in regard to the broad kinship networks that both sets of migrants depended upon. Officials also sought to develop examination protocols of bones and other body features that would definitively prove the age of young migrants, to prevent “adults” from cheating their way into the country. These discussions depended upon the idea that black and brown bodies matured at different rates than white bodies, and therefore foolproof tests needed to be developed to assist immigration officials who might be taken in. Thus, the border was an important site for the production of categories of family and youth, both of which were racialized. This process helped to create black and brown youth as a distinct and problematic category for a nation re-racialized as white in the years of its decolonization from empire.