China/Asia Population Imbalance and Effects

The Peking Duck has an article from Foreign Policy on the possible effects of China's distorted sex ratios.

Thanks in large part to the introduction of the ultrasound machine, Mother Nature’s usual preference for about 105 males to 100 females has grown to around 120 male births for every 100 female births in China. The imbalance is even higher in some locales—136 males to 100 females on the island of Hainan, an increasingly prosperous tourist resort, and 135 males to 100 females in central China’s Hubei Province. Similar patterns can be found in Taiwan, with 119 boys to 100 girls; Singapore, 118 boys to 100 girls; South Korea, 112 boys to 100 girls; and parts of India, 120 boys to 100 girls.

Is Taiwan really so high? In any case, comments on the Duck are down, and I wanted to post this link to a longer discussion of the same idea in the Chronicle of Higher Education. So there it is....

UPDATE: James adds a great link below to a Slate article:

Oster was suitably intrigued. She set out first to see if she could use data to confirm Blumberg's thesis. A vaccine for hepatitis B, she learned, had been available since the late 1970s. She found good data on a U.S. government vaccination program in Alaska. Before the vaccinations began, Alaskan natives had a historically high incidence of hepatitis B as well as a high birth ratio of boys to girls. White Alaskans, meanwhile, had a low incidence of hepatitis B and gave birth to the standard ratio of boys to girls. But after a universal vaccination program was carried out in Alaska, the Native Alaskans' boy-girl ratio fell almost immediately to the normal range, while the white Alaskans' ratio was unchanged. A vaccination program in Taiwan revealed similar results.

Convinced now of the relationship between hepatitis B and birth gender, Oster set out on a vast data mission to determine the magnitude of that relationship. She measured the incidence of hepatitis B in the populations of China, India, Pakistan, Egypt, Bangladesh, and other countries where mothers gave birth to an unnaturally high number of boys. Sure enough, the regions with the most hepatitis B were the regions with the most "missing" women. Except the women weren't really missing at all, for they had never been born.

If you believe Oster's numbers—and as they are presented in a soon-to-be-published paper, they are extremely compelling—then her detective work has established the fate of roughly 50 million of Amartya Sen's missing women. Her discovery hardly means that Sen was wrong to cry misogyny, at least in some parts of the world: While Oster found, for instance, that Hepatitis B can account for roughly 75 percent of the missing women in China, it can account for less than 20 percent of the boy-girl gap in Sen's native India. The culprits behind the disappearance of the 50 million women whom Oster did not find are likely the horrible ones that Sen and others have suggested. But Oster's analysis does show that economics is particularly useful for challenging a received wisdom—in this case, one that was originally put forth by another economist.

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