[Caution: thar be biases & politics ahead!] I realize that I've hijacked this thread way off topic, but here are some papers: http://belfercenter.ksg.harvard.edu/files/hudson_and_den_boer_spring_2002.pd... A Surplus of Men, A Deficit of Peace Valerie M. Hudson and Andrea Den Boer Security and Sex Ratios in Asia’s Largest States "One overlooked wellspring of insecurity, we argue, is exaggerated gender inequality." "We first quantify the scale on which sex ratios are being altered in Asia, then estimate the number of resulting surplus young adult males currently present in Asia’s two largest states, China and India, as well as projected to the year 2020. Next, we discuss behavioral syndromes associated with surplus young adult male groups, and investigate the role of such groups in instability and violence within and between societies in several historical cases." "Given our focus on security, we are most interested in bare branches [surplus males] who are in the age group 15–34/35, as this is the male age group that commits the preponderance of violence within a society. How many young adult bare branches are there now, and how many are there expected to be in the next two decades in the two most populous nations on earth, China and India? Generally speaking we will be seeing 29–33 million young surplus males in China in twenty years and 28–32 million young surplus males in India at that same time." "In sum, these young surplus males may be considered, relatively speaking, losers in societal competition." "The behavior of young surplus males also follows a broadly predictable pattern. Theory suggests that compared with other males in society, bare branches will be prone to seek satisfaction through vice and violence, and will seek to capture resources that will allow them to compete on a more equal footing with others." "Cross-culturally, an overwhelming percentage of violent crime is perpetrated by young, unmarried, low-status males." "The reproductive strategy chosen—that of high sex ratio—coupled with primogeniture ensured, in Boone’s words, “political instability, warfare, and territorial expansion.”" "Nevertheless, we understand how their analysis of 448 populations could result in the conclusion that “we are most likely to find unbalanced sex ratios when warfare is present.” See Divale and Harris, “Population, Warfare, and the Male Supremacist Complex,” American Anthropologist, Vol. 78, No. 3 (September 1976), pp. 531, 528." "India and Pakistan, both high sex-ratio societies, are unlikely to settle the conflict peacefully" "Nevertheless, it should never be forgotten by policymakers on either side of the Paciªc that the worst-case scenario implies that China may have close to 40 million young adult bare branches to spare in twenty years, and that the government may at that point ardently wish to see them give their lives in pursuit of a national interest. The alternative is to allow them to remain a threat to national interest, which may increasingly be seen as an untenable policy position by the government." "We suggest that societies with young adult sex ratios of approximately 120 and above are inherently unstable, and both China and India are, at this writing, nearing that level and will probably surpass that level in the next two decades." http://www.japss.org/upload/12.ross.pdf An “army of bachelors”? China’s Male Population as a World Threat http://anon-ftp.iza.org/dp3214.pdf Sex Ratios and Crime: Evidence from China’s One-Child Policy http://deepblue.lib.umich.edu/bitstream/handle/2027.42/97286/j.1538-165X.200... Bare Branches: The Security Implications of Asia’s Surplus Male Population by Valerie M. Hudson and Andrea M. den Boer. Cambridge,MA, MIT Press, 2004. 400 pp. $35.00. "Males are more violent than females, in part because of higher levels of testosterone. Men without women are far more violent than are men with women. Testosterone levels drop significantly and quickly when men marry." "The authors use historical cases to show high instability in countries with “exaggerated sex ratios.” Typically, high-sex-ratio countries have authoritarian governments" At 01:43 PM 11/6/2015, Fred Lunnon wrote: Is the proof constructive, and tell us who they're going to fight? More generally, does it offer an effective algorithm to discourage the human race from constantly turning every scientific advance into an agent of misery? WFL On 11/6/15, Henry Baker <hbaker1@pipeline.com> wrote:

The excess male Chinese are called "Chinese Remainders", and the fact that this leads to war is called the "Chinese Remainder Theorem". ;-)

At 12:56 PM 11/6/2015, Henry Baker wrote:

...

"It's estimated that by 2020, China will have 24 million more men than women of marriageable age on the mainland"

http://english.cri.cn/7146/2013/02/26/2702s750680.htm

Of course, artificially high sex ratios like this in human history are always resolved the same way: war. The young men kill one other until the problem has resolved itself.