If you were born in the UK, then your religion (if any) would probably be Christian. If, however, you were born in Morocco, you would probably be a Muslim. This shows (so the argument goes) that religious belief is not something that determined by a calm consideration of the evidence, but rather by where, and by whom, you were raised.
There is, however, a rather glaring problem with this argument, in that it applies to the pluralist who thinks that all religions are equally valid (or equally invalid). If the pluralist had been born in Morocco, he probably wouldn’t be a pluralist: he too would be a Muslim.
It is, therefore, a self-defeating argument, because the person advancing it is claiming: “All religious claims are culturally determined, except the one I am making right now.”
To be sure, cultural and historical conditioning make truth-claims difficult to test. But no-one – believer nor unbeliever – is exempt from testing his or her truth-claims, however, hard that may be.
(See Keller, The Reason for God, p11)