Most non-believers claim to be champions of reason, logic, rationality...but to the contrary, the non-theist usually ends up being the more illogical when it comes to world view issues, evident by numerous fallacious statements made in any given conversation. Normally, this comes about because the atheist, agnostic, etc are very good at making assertions, but very bad at making arguments. Two very common fallacies include the Genetic Fallacy and the Appeal to Pity.
Genetic fallacy#1 "You are only a Christian because you were born in the United States."
Notice, this is an assertion...not an argument, and therefore, the non-believer is in a tricky situation because the one who makes the claim, bears the burden...and this presents a problem for someone who commits the genetic fallacy because the origin of one's beliefs or claims does not confirm nor deny the validity of such a belief or claim.
I can believe that 2+2 = 4 because I learned it from a text book or because I learned it from Sir Isaac Newton...it does not matter what my source of belief is, what matters is whether or not the belief is true (i.e Explanatory Power, Cumulative Support)
So if the non-believer really wants to be a champion of reason, they must provide an argument with valid reasons, not simply dodge reality by stating fallacious assertions.
Tactic: Use a question to show them their fallacy by turning it back on them:
"So is it your belief that the only reason I am a Christian is because I grew up in a Christian society?"
They have to answer yes to this question based on their claim...
...now simply reply, "Well, you just believe that because of the society in which you grew up in."
In the next few posts, look for Genetic Fallacy #2, (“Christianity is a crutch for the weak”) and the Appeal to Pity fallacy, (“You mean that all of those other religions are wrong and their followers are going to hell?”)