“There is occasional speculation that synthetic biology might be used to adapt a natural pathogen to be active only against a specific human race. This is based on a misunderstanding of our species; humans do not have separate ‘races’ in the sense that a geneticist would recognize. Our species is a continuum: some versions of genes (alleles) do turn up at different frequencies in different ethnic groups, but this is a statistical property only. There are no absolute genetic differences that separate peoples on opposite sides of even a ‘racial’ conflict that would make one side vulnerable and the other safe.”