Economist Emily Oster says newly available data prove that the hepatitis B virus can’t explain China’s skewed sex ratios, after she made waves with earlier research that asserted the opposite.
World Bank economist Monica Das Gupta was one of the early critics of Ms. Oster’s work. She pointed out, in a paper titled “Explaining Asia’s ‘Missing Women’: A Look at the Data” that in Chinese families whose first children were daughters, later births tended to be sons. That suggested that families that had girls already were taking measures to ensure they would have a son. And Ms. Oster responded.
Then economists Ming-Jen Lin and Ming-Ching Luoh from National Taiwan University found data from a hepatitis B immunization program Taiwan launched in 1984 that covered three million births. It showed that for children born to women who carried the virus, male-female sex ratios were only slightly elevated, suggesting hepatitis B could explain only 0.9% to 1.8% of China’s missing women. They wrote a paper titled “Can Hepatitis B Mothers Account for the Number of Missing Women? Evidence from Three Million Newborns in Taiwan.”
Ms. Oster found a large, continuing study of hepatitis B in rural China. Working with the local public-health authorities, she collected data on child gender from 67,511 participants, 15% of whom carried the virus. This research led to her latest paper, “Hepatitis B Does Not Explain Male-Biased Sex Ratios in China.”
In related research, one paper looks at how higher relative income among women in China reduces the missing women problem. Looks at tea cultivating areas (where women have a comparative advantage) versus orchard growing regions. Written by Nancy Qian, it’s titled “Missing Women and the Price of Tea in China: The Effect of Sex-Specific Income on Sex Imbalance.”
Nancy Qian and Ming-Jen Lin also looked at how increased abortion rates in Taiwan led to lower rates of female infant mortality. Their paper is titled, “More Missing Women, Fewer Dying Girls: The Impact of Abortion on Sex Ratios at Birth and Excess Female Mortality in Taiwan.” –Justin Lahart