送交者: xj 于 2005-11-08, 15:54:06:
回答: 乙肝是造成中国男多女少的主要原因 由 Latino2 于 2005-11-08, 15:09:45:
I just write some random notes here. Probably I can give careful thoughts later.
As usual, the political econ paper is messy and hard to follow. Anyway, I summerize here about her rationales.
1) some studies on family history pointed out the possibility of HBV increase male/female sex ratio. This are individual level studies which I believe can answer the question definitively.
2) some birth cohort analyses (time series) are also suggestive. Unfortunately, the Taiwan study doesn't fully support her view.
3) then she goes to country level analyses, using the sex ratio from separate populations. The number of missing women are derived from regression.
Questions remain, however, why and how can HBV affect sex ratio? biological effects? To be honest, I never heard of this in any CHinese study.
It is more likely the HBV effect is due to economic reasons. As we known, HBV infection is more common among rural population, and among poor people. Furthermore, HBV infection tends to cluster in regions. For example, Qidong county, Jiangsu province has the highest rate of HBV infection, while the neighboring Hanmen county, Jiangsu and Congmin county, Shanghai, have national average level of HBV infection.
It also happens that rural and poor people are more likely kill female fetus than rich and city dwellers. The social norm among rurual people are different from that of city dwellers.
Furthermore, HBV infection is not related to sex ratio geographically within China (needs examples).
Ecological anlyses subject to ecologic fallacy, that is, the the ecological correlation is not the underlying causation because the accused individuals are not the people who get the outcome. There are some other factors hidden in the population.