In an era of increased global mobility, more children are born into mixed multi-national families, and hence more individuals become multiple citizens on the basis of their birth circumstances. Jus sanguinis, on its own or in combination with jus soli, can create a legal entitlement to multiple nationality. Some states, like Norway or Germany, have imposed restrictions on birthright dual citizenship, but not without stirring social protest. This chapter discusses whether such restrictions are legitimate and whether birth circumstances alone (blood ties to another citizen or birth on the state’s territory) ought normatively give individuals moral entitlements to multiple nationality. I maintain that such arguments in favour of multiple citizenship – grounded in the special relationship between children and their parents or in the parents’ ‘right’ to transmit citizenship to their children and the children’s ‘right’ to take on this citizenship – are misguided and reflect a grave misunderstanding of the nature and particularity of citizenship as such. I conclude by introducing a policy proposal – a system of citizenship renewal – that would reform birthright (multiple) citizenship.