Members of the network might be interested in the following paper by Emily Oster of Harvard:

 

Hepatitis B and the Case of the Missing Women

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 efforts indicate that carriers of the hepatitis B virus have offspring sex ratios as high as 1.5 boys for each girl. Hepatitis B is common in many Asian countries, especially China, where some 10 to 15% of the population is infected. Using data on hepatitis B prevalence by country as well as estimates of the effect of hepatitis on sex ratio drawn from a wide range of sources, I find 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 less than 20% in India, Pakistan and Nepal.

 

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=664625

Peter Craig