"If you had been born in Saudi Arabia, you would have a 98% chance of being a Muslim."
You've heard that argument already, right? You have also probably heard the rebuttal that it's an example of the Genetic Fallacy: The fact that what you believe depends on where you were born does not mean that what you believe is false.
In a sense, those who object to the argument on those terms are right. When interpreted as an argument against god, it just doesn't hold. However, the true power of the argument is not as a tool to prove there is no god and I am not sure whether it is mostly the believers who like to interpret it as such, so they can have an easy job tearing it down, or the non believers, who didn't really think it through.
The fact that, exceedingly, religious affiliation depends on geography or family history, is only useful together with the fact that, for almost every believer, geography is the main reason why they choose to believe in a particular god. All other possible reasons play a very minor role. If this weren't true, we'd see much more of a patchwork in the map below.
The argument is not that, if your belief depends on geography and family history, your god is likely false. That would be an example of a genetic fallacy.
The argument is that, if your belief depends only on geography and family history, then it has no more chances of being true than the god of the muslim guy, or the hindu guy, or the christian guy who lives right across the border.
And this is not a genetic fallacy.
