Presumably, the author meant that the two most likely nations to birth the 7 billionth human are China and India. I doubt the intended comparison was between the set {x ∈ nations : x = China or x = India} and its complement {x ∈ nations : x != China and x != India}.
I realize I'm being a little pedantic, but the original phrasing does read as the probability of it being in India or China is greater than the rest of the world combined.
