Until recently, public health and genomics have rarely come together although both have long aimed to improve population health. The emerging fi eld of public health genomics represents this much-needed convergence. This new subspecialty of twenty-fi rst-century public health is hybrid in its composition, made up of knowledge strands from public health and genomics sciences, and is defi ned as ‘the responsible and effective translation of genomebased knowledge for the benefi t of population health’ [1]. This consensus defi nition was reached at an international meeting held in Bellagio, Italy, in 2005. Rather than viewing populations as a homogenous entity, public health genomics fi rmly recognizes the hitherto silent heterogeneity in population substructure as rooted in genomics and genome-environment interactions. Described in another way, public health genomics is an invitation to rethink the current efforts for stratifi ed medicine in the broader context of populations.