Big and tall soldiers are more likely to survive battle: A possible explanation for the ‘returning soldier effect’ on the secondary sex ratio

Citation

Kanazawa, S. (2007). Big and tall soldiers are more likely to survive battle: A possible explanation for the 'returning soldier effect' on the secondary sex ratio. Human Reproduction. vol. 22 (11) pp. 3002-3008

Abstract

It is widely known that more boys are born during and immediately after wars, but there has not been any ultimate (evolutionary) explanation for this ‘returning soldier effect’. Here, I suggest that the higher sex ratios during and immediately after wars might be a byproduct of the fact that taller soldiers are more likely to survive battle and that taller parents are more likely to have sons. METHODS: I analyze a large sample of British Army service records during World War I. RESULTS: Surviving soldiers were on average more than one inch (3.33 cm) taller than fallen soldiers. CONCLUSIONS: Conservative estimates suggest that the one-inch height advantage alone is more than twice as sufficient to account for all the excess boys born in the UK during and after World War I. While it remains unclear why taller soldiers are more likely to survive battle, I predict that the returning soldier effect will not happen in more recent and future wars.

URL

https://doi.org/10.1093/humrep/dem239

Reference Type

Journal Article

Journal Title

Human Reproduction

Author(s)

Kanazawa, S.

Year Published

2007

Volume Number

22

Issue Number

11

Pages

3002-3008

DOI

10.1093/humrep/dem239

Reference ID

689