Update: I put this post up before a very long road trip. When I checked the comments on my smartphone 10 hours later at a truck stop things had clearly gone in an unproductive direction. So I closed comments. In the future I understand that it will not do for me to put up a post when I won’t be able to monitor initial comments, as excising inappropriate ones after the fact fragments the conversation too much. Live and learn.

For the record, I have no issues with being impolitic on the substance of matters. But thread-jacking as occurred below when there’s so much low hanging fruit to discuss is not acceptable. Speaking of which, in response to S. R. Datta’s mooting of the issue of hepatitis as the reason for sex ratio distortion in China, that hypothesis seems to have been rejected, including by the scholar who originally forwarded it. Obviously that may not be true generally, though let us note that sex ratio imbalances are well known from the historical record, and they often vary as a function of time and class (e.g., medieval European nobility seemed to exhibit son preference, while peasants did not, at least as adduced from the ratio of the sex of buried infants). I think the Trivers-Willard hypothesis may explain some of these trends across human history.

End Update

Several readers have pointed to the recent, unfortunately predictable, story coming out of the Indian census, Selective Abortions Blamed For Girl Shortage In India:

Dr. C. Chandramouli, India’s census commissioner, says the numbers don’t lie: The girls are missing.

Among children under 6 years old in India today, there are only 940 girls for every 1,000 boys. Worldwide, it’s around 986 to every 1,000.

Chandramouli says this is a continuation of a trend that was first seen clearly in the 2000 census — but the new figures show the problem is spreading.

“It has to be said that what was predominantly a North Indian phenomena of a few states has now spread across the country, and we see a uniform decline all over the country, so that is what is more distressing,” he says.

First, in the short term economic development can lead to the spread of practices through emulation of dominant elites. But, in the long term one can see a reversal of the preference for boys to girls. In Japan the shift occurred 20 years ago. In Korea the change is happening now. One hopes that the same switch will occur with China and India, though it seems unlikely that these nations will become as wealthy on a per capita basis as Japan or Korea in the near future, so it would have to be driven by non-economic factors as well (the drop in fertility in some nations preceded economic growth, to the surprise of demographers, so it can happen).

But it must be remembered that regional differences persist, as is evident in this map: Continue reading →