Gwynn Guilford in The Atlantic:
There’s a close relationship between surging populations of young men and “revolutions, wars and upheavals,” argue Ajay Kapur, Ritesh Samadhiya, and Umesha de Silva. The Bank of America/Merrill Lynch analysts cite “civil war in medieval Portugal (1384), the English Revolution (1642-51), the Spanish conquistadores ravaging Latin America … the French Revolution of 1789, and the emergence of Nazism in the 1920s in Germany.”
Similar problems may be developing in emerging markets right now. While the analysts point out that the ratio of young men to older men has peaked in most emerging markets—generally a good sign for political stability—the raw number of males aged 15-29 is “massive.”
When there aren’t enough jobs to employ the supply of young men, that can galvanize conflict, argue the analysts—as can stagflation, rising income inequality, unaffordable property, and other problems facing emerging markets. Particularly if they’re unmarried, these young men have less to lose by banding together and committing crimes, unrest, or violence.
The latter point is a particular concern in China and India, where a cultural preference for boy children has led to sex selection of infants that now means there are tens of millions more young men than young women.
More here.