The apparent risk of childhood leukemia resulting from paternal pre-conception radiation exposure found among children of the Sellafield (West Cumbria, UK) workforce is compared with the apparent risk in a number of other epidemiological studies. In particular, the extent of the incompatibility of the leukemia pre-conception exposure risks in the offspring of the Sellafield workforce born in the village of Seascale with the risks for those born in the rest of west Cumbria, and with the risks in the offspring of the Japanese bomb survivors, the Ontario radiation workers, and the Scottish radiation workers is discussed. A variety of animal data relating to the possibility of leukemia arising as a result of parental pre-conception exposure is also considered. It is concluded that the extent of the inconsistency of the leukemia risks in the Seascale data with this body of epidemiological and experimental data makes it highly unlikely that the association observed in the West Cumbria dataset represents a causal relationship.