The "youth bulge" hypothesis says that whenever the proportion of young men in the population was very high, their unhappiness with their future prospects - i.e., their inability to get jobs and sustain a family and their future - often ended in imperialistic or rebellious movements & endeavours, such as the crusades, genocides, and terrorism.

Historians seems split about this hypothesis as a mono-causal explanation and red thread for human history. I'm partly convinced that the youth bulge might be a necessary, though insufficient condition for imperialistic movements. However, it's hard to build an opinion without historical demographic information.

According to acknowledged historians, what were the main arguments for and against the youth bulge hypothesis? I would appreciate an in-depth explanation of those arguments.

  • Do you mean that this happens when new-born girls are killed, as in China? Otherwise how can there be a surplus of males?
    – Lev
    Oct 15, 2011 at 5:28
  • @Lev it mainly happens when the birth rate is increasing/exploding historically (you are right, of course as many girls a born too, but there is only a limited number of jobs for young men in patriarchal societes/cultures, so the 3rd/4th son in family has not really a future and according to "youth bulge" hypothesis tends to leave his birth place as there is no perspective for him to nourish a family and follows imperialistic/rebellious/terroristic movements out of lacking perspective/anger. For terrorism/imperialistic war you need many young men who have nothing to lose, kind of social valve
    – Hauser
    Oct 15, 2011 at 11:22
  • Interesting question. This sort of crosses over with 'mass psychology', but is definitely history too. :-)
    – Noldorin
    Oct 15, 2011 at 17:56

2 Answers 2


A recent report by USAID offers a brief but insightful view on some of current research on 'Youth Bulge' hypothesis. Some of the key take-away are:

  • The common thread across the latest research is that youth bulges alone do not cause conflict. Rather, when unstable politics and social deterioration are combined with large numbers of disadvantaged young men, then new problems arise.

  • The latest findings here emphasize regime type and factionalism, poverty/development, “bad neighbors,” and the level of state discrimination. Youth bulges appeared significant in the PITF’s early attempts at modeling, but when measures of regime characteristics were included,the significance dropped away (Goldstone et al 2005, 12-13).

  • Urdal & Hoelscher 2009). Urdal has found no correlation between youth bulges, urbanization and violence, although the caveat here is that other factors, such as absence of democratic institutions, low economic growth and low levels of secondary educational school are associated with disturbance (Urdal & Hoelscher, 1).

  • the link is broken, can you give the full name of th report and maybe a new link?
    – mart
    Nov 20, 2015 at 7:30
  • pdf.usaid.gov/pdf_docs/pnadt635.pdf YOUTH BULGES AND CONFLICT this one?
    – mart
    Nov 20, 2015 at 7:39

A (male) youth bulge sometimes occurs when the birth rate is FALLING. That's because most men prefer to marry women younger than them. So if the birth rate is falling, there are more older men of the earlier period than younger women of the later period.

This happened with American cohorts born in the 1960s (and in certain other parts of the world). One observation (possibly not a consequence), was that those young men born in the 1960s made better soldiers in the Persian Gulf War than young men born in the 1940s and early 1950s in the Vietnam war.

The men born in the 1940s and early 1950s enjoyed a higher ratio of women born slightly later, from 1945-1960. That may be one reason that cohort of men preferred to "make love, not war."

  • 1
    All the deaths (and flight from) the Vietnam war may have had a bit of an effect there too. I know my Dad is a year younger than my Mom, perhaps because my Mom's high school sweetheart (who was older) was killed in Vietnam. A lot of the young women protesting at the time had very personal reasons for hating that war. Also, as young people staying behind during wartime, I remember them both having what look today like rediculously good white-collar jobs (and a house!) for people in their 20's with no degree.
    – T.E.D.
    Sep 7, 2012 at 20:44

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