Just to bring something up - remember when China had the one-child policy? that was NOT a good idea. Many people left baby girls in enclosures where they would basically starve to death - All because they wanted boys to carry on the bloodline!
Years on and China still hasn't recovered, there is still a massive imbalance between males and females and certain age ranges.
See this population pyramid?
Imagine if India underwent the same thing. I can see only disaster and death in both directions. Limit the number of children? Many will die for being the wrong gender/height/whatever. Let the growth continue? Even less resources to share amongst the world/possible lower GDP/mass immigration leading to a loss of both the Indian culture and the culture of countries that receive the migrants/strain on resources in many countries (education, medicine, jobs, etc).
The question is - Which is the lesser of two evils?