[araneae]

Yes, an aging population is a problem in any country that's seen a drop in fertility rates. This effect is actually the worst in Japan, followed by Italy.

re: lack of women

The nice possibilities are polyandry, in which one female marries multiple males. Another is the the devaluing of males. I.e. because of the rareness of females, males may some how compensate their families, and girls could become more valuable for parents to have. A third "nice" possibility would be to import females from other countries, or for males to emigrate to higher female areas. This would diffuse the problem, although if China's population becomes high enough it will just spread the problem to everyone.

The not-so-nice possibilities include increased male-male competition for mates (which happens in all species, including humans; single males are much more likely to be murdered or be murderers than their married counterparts/women in all cultures.) In history, it would be quite common for violence to occur at least in part for the purpose of procuring more females.

We can't predict it, but there's likely to be some sort of fallout. Maybe there's a technological solution: androids? Virtual reality brides? Prostitution? The excess boys need something to keep them occupied. Perhaps porn will be sufficient.

[m_eiman]

single males are much more likely to be murdered or be murderers than their married counterparts/women in all cultures

You don't think that that might have more to do with single males being younger and more likely to do risky things in general? Also, being married implies a commitment to being part of a family for a long time - and not do things that are likely to get you killed.

[araneae]

Younger males do risky things because that's when they're looking for mates. Death rates start to spike for males in their teens and then decline in their mid twenties, whereas the lines for females smoothly increase as they age.

That aside, if you do a regression on the incidence of murder rates, both age and marriage status are significant. So yes, age explains some of it. So does marriage status, independently.

Regardless of the reason that marriage keeps you out of violent situations, the point still stands that being unmarried is a risk factor for violence.

[catzaa]

You should remember that there is already a selection process going. Most women will refrain from marrying a violent person. The violent person will therefore be "unmarried" yet the high crime rate hasn't anything to do with marraige.

[araneae]

Then why do so many females like Twilight?

[radu_floricica]

Both the risk and potential payoff are far greater for male then female. A woman can hope to have around 5-6 surviving children, with little risk to have none. A male has a real risk of dieing without children, but on the other hand the best case scenario is in the hundreds of offspring.

But the real consequence of a bigger male-to-female ratio will probably be plain old fashioned competition. Some men, especially young, will go the "flashy" way, but for most it will simply mean that having outstanding performance in whatever they do is much more important. Wouldn't want to be one of them, but for the society as a whole is probably good.

[Nekojoe]

Although this article [1] is 9 years old, it's still relevant as it shows the impact of the one child policy.

Women become valuable commodities. I've heard stories about rural Chinese girls being scammed and promised offers of marriage from rich men in the city. In reality they're sold into a life of slavery.

At the other end of the scale though more educated women in China can take their pick of males.

[1] http://news.bbc.co.uk/1/hi/world/asia-pacific/927309.stm