While they are the most population-dense areas and are growing faster than other places in the world, I'm pretty sure it's more likely that the 7 billionth person won't be born in India or China.
Therefore the odds of it being India or China is ~ (17.4+27.6)/142 ~ 31%.
Fact: Considering that No country has a birth rate larger than 3x India and only China has a population larger than India, India has the maximum # births/year in the world.
It takes all of 2 mins to calculate. All facts from here: http://en.wikipedia.org/wiki/List_of_sovereign_states_and_de...
Birth rate world-wide: 20.3/1000. Population: 7 billion :-)
Total # births: ~ 142 million.
Birth rate India: 23/1000. Population: 1.2 billion.
Total # births: 27.6 million.
Birth rate China: 13/1000. (That should surprise people). Population: 1.34 billion.
Total # births: 17.4 billion.
Therefore the odds of it being India or China is ~ (17.4+27.6)/142 ~ 31%.
Fact: Considering that No country has a birth rate larger than 3x India and only China has a population larger than India, India has the maximum # births/year in the world.