[quote]Hepatitis B theory

Sex-selective abortion, infanticide, and abandonment may not be the only causes of sex ratio imbalances in the countries mentioned above. Research indicates that women infected with the hepatitis B virus are 1.5 times more likely to give birth to a male. The researcher, Emily Oster, says that the higher rates of hepatitis B in China could account for 75% of the "missing girls."[13] However, new demographic research casts doubt on the hepatitis B theory. Das Gupta found that data from a huge sample of births in China show that the only women with elevated probabilities of bearing a son are those who have already borne daughters. [14]

Work by Emily Oster notes that women infected with hepatitis B virus are more likely to bear males than uninfected women.[citation needed] Her 2005 publication in The Journal of Political Economy suggests that in the past, the prevalence of hepatitis infection may have accounted for 75% of the sex ratio imbalance in China, 20% to 50% of the imbalance in the Middle East and Egypt, but less than 20% of the imbalance in India, Pakistan, Bangladesh, and Nepal.[citation needed] This is an active area of research and these findings are controversial.[citation needed] Today's concentrations of sex ratios imbalances are regional -in North-West India or East China- and demographic -among women whose first child was a girl and do not correspond at all to known epidemiological features.[citation needed[/quote]