Regardless of the exact reason that taller soldiers are more likely to survive battle, the phenomenon of the “returning soldier effect” is not likely to be observed and repeated in more recent and future wars. This is because a substantial proportion of the population must be deployed for the proposed mechanism to produce excess boys in the population. Military forces of advanced western nations today do not require as many soldiers as they used to. The transition to smaller military forces is reflected in the discontinuation of mandatory draft in most western nations.
With much smaller proportions of the population mobilized in wars, the returning soldier effect is not likely to be repeated, even if taller soldiers are still more likely to survive battle and even if taller parents are more likely to have sons. The higher offspring sex ratios (more boys) among surviving (and returning) soldiers will not significantly shift the offspring sex ratio of the whole society. Even though an increasing number of young men and women are mobilized in the current war, the rate of mobilization in the United States is nowhere near one-third (the rate of mobilization in the United Kingdom during World War I). Probably for this reason, more boys were not born during more recent wars, such as the Iran-Iraq wars in 1980-1988 and the 10-day war in Slovenia in 1991. Nevertheless, if the height advantage of surviving soldiers over fallen soldiers in the UK during World War I is generalizable to other belligerent nations in both World Wars, then this can potentially solve one of the long-standing mysteries in evolutionary biology and psychology.
