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Hepatitis B and the case of the missing women
Perhaps there are biological explanations to explain Sen's "missing women" phenomenon
Authors:
E. Oster
Publisher:
Harvard University Library, 2005
This paper complements Amartya Sen's hypothesis on the world's "missing women" -- the idea that millions of women are missing from the world due to sexual violence and discrimination -- by offering a biological explanation for the sex disparity. This paper hypothesises that the sex ratio imbalance may also be due to the effect of Hepatitis B on birth ratios.
In many Asian countries the ratio of male to female population is higher than in the West -- as high as 1.07 in China and India, and even higher in Pakistan. A number of authors (most notably Sen, 1992) have suggested that this imbalance reflects excess female mortality and, as a result, have argued that as many as 100 million women are missing." This paper proposes an explanation for much of the observed over-representation of males: the hepatitis B virus.
Evidence drawn from the existing medical literature as well as new studies of recent vaccination reports indicate that carriers of the hepatitis B virus have offspring sex ratios as high as 1.55 boys for each girl. This is strongly supported by cross-country evidence on hepatitis B prevalence and sex ratios at birth. Hepatitis B is common in many Asian countries, especially China, where some 10 to 15% of the population is infected. Using data on viral prevalence by country as well as estimates of the effect of hepatitis on sex ratio drawn from a wide range of sources, the author found that hepatitis B can explain about 45% of the missing women: around 75% in China, between 20% and 50% in Bangladesh, Egypt, and West Asia, and under 20% in India, Pakistan and Nepal.
The author uses her findings to make determine interesting policy and practical applications about the effects of Hepatitis influenced births. One such implication is slower population growth rate and more all-female families than would be predicted by the overall sex ratio at birth. The overall sex ratio in the population will be lower than would be produced naturally by Hepatitis B. The findings also shed light on the effect of a Hepatitis B vaccine: as fewer and fewer carriers are giving birth, sex ratios at birth in these countries are likely to continue to decline, resulting in more female babies than in the past. With a strong tradition of son preference, one might expect more sex-selective abortion and other interventions designed to once again increase the probability of a male child.
The missing women problem has historically been understood as arising from a difference in preferences -- some countries value women less than others, and in these places women are mistreated to the point of excess mortality. The conclusions in this paper argue that perhaps preferences play a smaller role than previously expected, and biological differences a much larger one.
