The ‘returning soldier effect‘ is the phenomenon which indicates more male births supposedly occur during and immediately after wars.
Listen beautiful relax classics on our Youtube channel.
Research by Brian MacMahon and Thomas F. Pugh looked into the demographic data in the United States between 1945 and 1947, particularly the sex ratio of live-births, and they observed an increase in this figure, taking note that more boys had been born.
Kanazawa Satoshi also looked into the birth records of Britain after World War I. He found the same trend of having more male births directly following the war. So, the idea of the ‘returning soldier effect’ originated from all these observations and research. However, why this was the case is something that wasn’t particularly explored.
Kanazawa had proposed that the reason for this difference in sex ratio of live births may have something to do with the soldiers who survived the wars. He posited that it was because of the physical features of the surviving soldiers, i.e. being bigger and taller, that gave rise to this phenomenon.
However, research into the aftermath of the Iran-Iraq War had recorded the reverse effect. William H. James explained this outcome by saying that the stress experienced by pregnant women was the reason for the decline of male births. Plus, there’s no definitive evidence pointing to physical features as the primary factor determining the sex of babies.
Valerie Grant, on the other hand, explains that the changing hormone levels of women during wars might have pushed them to adopt more dominant roles thus resulting in a relative increase in male births.
Is it even possible to predict whether a baby will be a boy or girl by looking at the environmental, physical, or social factors? I think it could just have been a coincidence that more baby boys were born after the wars, and that it was equally probable that either a boy or girl would have been born.
(Image credit: soldiersmediacenter/Wikimedia Commons)
Source: neatorama