The worldwide war on baby girls

from The Economist:
The spread of fetal-imaging technology has not only skewed the sex ratio but also explains what would otherwise be something of a puzzle: sexual disparities tend to rise with income and education, which you would not expect if “backward thinking” was all that mattered. In India, some of the most prosperous states—Maharashtra, Punjab, Gujarat—have the worst sex ratios. In China, the higher a province’s literacy rate, the more skewed its sex ratio. The ratio also rises with income per head.