Study: Why are Indian kids shorter than African ones?

The abstract (Harvard via ChrisBlattman):

Height-for-age among children is lower in India than in Sub-Saharan Africa. This presents a puzzle since India is richer than the average African country and fares better on most other development indicators including infant mortality. Using data from African and Indian Demographic and Health Surveys, we document three facts. First, among rstborns, Indians are actually taller than Africans; the Indian height disadvantage appears with the second child and increases with birth order. Second, investments in successive pregnancies and higher birth order children decline faster in India than Africa. Third, the India-Africa birth order gradient in child height appears to vary with sibling gender. These three facts suggest that parental preferences regarding higher birth order children, driven in part by cultural norms of eldest son preference, underlie much of India's child stunting.