Why do Christians become Christians?

[SteveII]

Except the hundreds of millions who haven't.

Yeh there are exceptions who just find the message of Jesus a nice one to follow.  I'm talking about the global majority who are born into being Christians.

So, how large does a pool have to be before hundreds of millions of people are not an exception? 

Okay, say we take the US statistic of 85% of Christians were born into a Christian home. You are claiming that these people only stay because of the "brainwashing" they received as children. The 15% adult conversions are exceptions. You are also concluding that the message that Christianity is a con (or however you want to characterize it) and science can prove it is not working on (319 million US population x 70.6% Christians = 225 million x 85% born into Christian homes) = 191 million people. And this is in the wealthiest country with cast amounts of information available to anyone with access to a computer (to say nothing about the education system's attempt to undermine faith). 

I don't think the numbers support your conclusion.