The clustered excess of childhood leukaemia and non-Hodgkin's lymphoma at Seascale, close to the nuclear reprocessing plant at Sellafield in the UK is well authenticated and has remained a 'current topic' for over a decade. Its root cause has not been established. Following a study suggesting that parental irradiation exposure prior to conception was a factor, a recent laboratory based report reopened the debate by indicating the potential for preconception, paternal irradiation (PPI) to result in increased or accelerated induction of lympho-myeloid malignancy in offspring subjected to a recognized leukaemogen. This short commentary presents those new findings in the light of the many and diverse epidemiological investigations of first generation malignancies following parental exposure, the majority of which indicate no real evidence to support the concept that patterns of lympho-myeloid malignancy reflect levels of PPI. Other experimental work supporting PPI are considered against unsuccessful attempts to reproduce them. The alternative, and more popular, hypothesis of infection spread via population mixing, which is more ubiquitous than confinement to nuclear localities, is introduced. Mechanisms of potentiation by PPI are considered, though the danger of applying these current findings to explain the enigma of Seascale, or any other cluster, is recognized.