Significance Family background—kinship—can propagate careers. Five decades of health science literature worldwide show that, among family-tied authorships, there are country-specific patterns of publication evolving over time; authors who are part of a kin tend to form distinctive collaborative networks. A certain level of kinship may have beneficial effects on the research outputs of a country, whereas greater or lesser amounts of kinship could have adverse effects. It is perhaps more important for nations to promote equal opportunities in academic careers than to attempt to contain nepotism. Just as kin build potent academic networks with their own resources, societies may do well to provide equivalent support for talented individuals with fewer resources, on the periphery of networks.