Here's a question for you Mr. Fundy. If you had been born in Mecca, Saudi Arabia, would you be a Christian or a Muslim. If you had been born in the highlands of Tibet, would you be a Christian or a Buddhist? If you had been born in the Mayan empire 1000 years ago, would you be a Christian or a pagan? Hmm...pretty random, isn't it...mostly geographical and temporal accident in fact.
As far as your 'examples' are concerned, without the help of modern medicine 5 out of 10 babies and their mothers would die during child birth because our head has to be so big for this brain. There is always a counter example.
"Mr. Fundy"? Ooh, I bet you say that to every Christian you meet. Thank you!

"mostly geographical and temporal accident in fact"? No, not true.
I was born and raised in a country that is 99% Roman Catholic. Yet, I was raised Southern Baptist. Southern Baptist? Imagine that.
Christianity is Middle Eastern. That's where it originated, in Palestine. We don't know exactly how many Christians exist in countries where Christians are tortured and killed, countries like China and all the Islamic countries. Christianity has been growing in China and South Korea. Christianity is big in Australia too.
Christians form the third largest group in Kerala, India. They have sometimes, even in some official documents, been called Nazaranis (followers of Jesus of Nazarene) or St. Thomas Christians.