Eminent historians in Canada have contended that pioneer societies often experience marked sexual imbalance in their early stages, having far fewer women than men. Certain Soviet historians tended to deny the existence of such a problem in Siberia. Since the two regions match each other in many ways (they enjoy similar geographical conditions, were settled by European peoples at roughly the same historical period for analogous purposes and were both governed in a centralised military/bureaucratic fashion), an investigation was undertaken into the reasons for Canadian and Soviet disagreements over the issue. Concentrating on the period of earliest exploration and settlement, before large-scale British immigration, the study predominantly compares Russian settlement in Siberia with its French equivalent in New France. Data from both sides make it quite clear that in the early stages there were fewer women than there were men, that the imbalances were overcome during a century or more in regions where agriculture was possible, but persisted in more northerly territories or unstable military zones. The sources from which women came were: interbreeding with indigenous peoples, government attempts to provide women for male settlers and rapid natural increase, with the probability that more female than male offspring survived. Clear parallels exist between the Siberian and Canadian experience, despite the cultural, economic and political differences. Soviet denials of an early imbalance seem to have been dictated by a need to prove that the USSR had never experienced colonialism of the type characteristic of the European empires.