The returning soldier effect is a phenomenon which suggests that more boys are born immediately after wars. This effect is one of the many factors influencing

human sex ratio The human sex ratio is the ratio of males to females in a population in the context of anthropology and demography. In humans, the natural sex ratio at birth is slightly biased towards the male sex. It is estimated to be about 1.05 worldwide or ...

. It was especially noticeable worldwide during and right after both of the World Wars. The phenomenon was first noticed in 1883 by Carl Düsing of the

University of Jena The University of Jena, officially the Friedrich Schiller University Jena (, abbreviated FSU, shortened form ''Uni Jena''), is a public research university located in Jena, Thuringia, Germany. The university was established in 1558 and is cou ...

, who suggested that it was a natural regulation of the status quo. Writing in 1899, an Australian physician, Arthur Davenport, used Düsing's findings to hypothesize that the cause was the difference between the comparative ill-health of the returning troops compared to the good health of their partners. Research published in 1954 by

Brian MacMahon Brian MacMahon (23 August 1923 – 5 December 2007) was a British-born American epidemiologist who chaired the Department of Epidemiology of the Harvard School of Public Health from 1958 until 1988. Best known for his work on the epidemiology ...

and Thomas F. Pugh showed that the sex ratio of white live births in the United States had shown a marked increase in favor of boys between 1945 and 1947, after

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

, with a peak in 1946. In 2007, Kanazawa Satoshi published a paper theorizing that the effect was due to "the fact that taller soldiers are more likely to survive battle and that taller parents are more likely to have sons". This was based on his research of

British Army The British Army is the principal Army, land warfare force of the United Kingdom. the British Army comprises 73,847 regular full-time personnel, 4,127 Brigade of Gurkhas, Gurkhas, 25,742 Army Reserve (United Kingdom), volunteer reserve perso ...

records from

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, which showed that "surviving soldiers were on average more than one inch (3.33 cm) taller than fallen soldiers". Other genetic explanations have been proposed. Valerie Grant attributed it to changing hormone levels of women during war, as they tended to "adopt more dominant roles". William H. James writing in 2008 gave an increase in coital rates by returning soldiers as a possible cause. He also noted that a fall in the ratio of male births had been recorded in Iran following the

Iran–Iraq War The Iran–Iraq War, also known as the First Gulf War, was an armed conflict between Iran and Iraq that lasted from September 1980 to August 1988. Active hostilities began with the Iraqi invasion of Iran and lasted for nearly eight years, unti ...

, "explained by psychological stress causing pregnant women disproportionately to abort male fetuses". The normal ratio is estimated to be some 1.03 to 1.06 males per female, which appears to compensate for the fact that child mortality rate among boys is slightly higher than among girls, and that adult men are more likely to die from an accident than women.

References

Aftermath of war Human sex ratio {{sociology-stub

See also

References