The study is disputed by a top Indian doctor:
http://news.bbc.co.uk/1/hi/world/south_asia/4601184.stm
Another, in-depth, article on this topic.
http://www.indiatogether.org/2003/aug/wom-sexratio.htm
The obvious riddle is that women will eventually become scarcer . . . . yet men need women to have more boys, yet they want boys not women to be born.
Isn't there also an inference that a population imbalance like this, weighted towards hordes of men, could lead to conflict either internally or regionally?
Cowperson