Most people oppose polygamy out of intolerance, but many social scientists offer a deeper objection: Polygamy simulates the allegedly awful social effects of high male/female ratios. Arnold's particularly worried:
If it were not for monogamy, the competition among males for females
would be so intense that there would be no social institutions. Men
could not work with one another in corporations, associations, or any
other joint ventures. Civil society would not exist.
I've never been convinced. Yes, intense male competition could take ugly forms. But it could just as easily stimulate industry and thrift, as men strive to out-compete each other economically. Now it looks like this is more than a mere theoretical possibility. Gender imbalance is plausibly a major cause of high Chinese savings rates - and therefore high Chinese growth! From an interesting write-up of Columbia's Shang-Jin Wei:
Wei worked with Xiaobo Zhang of the International Food Policy
Research Institute in Washington, D.C., to see if his hypothesis held
up, comparing savings data across regions and in households with sons
versus those with daughters. "We find not only that households with
sons save more than households with daughters in all regions," Wei
says, "but that households with sons tend to raise their savings rate
if they also happen to live in a region with a more skewed sex ratio."
The effect is significant. The household savings rate in China rose
from about 16 percent of disposable income in 1990 to over 30 percent
today, which is much higher than most countries. About half of the
increase in the savings rate of the last 25 years can be attributed to
the rise in the sex ratio imbalance.
This doesn't mean that China's gender imbalance is a good thing. But what's horrible about China's gender imbalance isn't the "broader social consequences." What's horrible is how China's imbalance arose: Selective abortion and infanticide fueled by its monstrous one-child policy. Isn't it shocking, then, that it's a lot more socially acceptable to defend coercive "family planning" in China than consensual polygamy in America?