Aren't most religious people like this? If you are born in Pakistan, chances are pretty high that you believe in Islam. Cambodia? Probably a Buddhist.
All Christians that I know, are born out of a Christian family. I see culture as the main driver of religion. Or do you expect if you take a Cambodian baby and place them in Pakistan, that they will grow up to be Buddhist?
I'm an atheist, and almost all people around me are atheists. What a coincidence! My wife is from a foreign country. All people around here are dedicated Christians. And guess what, she is also a Christian! What a double coincidence!