can identical twins have different religious beliefs?

[bennyboy]

Just thinking about genetically identical twins, triplets, etc.
If they are all exposed to the same upbringing, whatever that may be, would they have the same propensity to believe or not believe?

No, I don't think so. The butterfly effect will take care of that. There is no such thing as the "same upbringing," as one may stub a toe while the other does not, causing them to experience subsequent moments in different emotional states. On must take the window seat or the aisle seat on the school bus, exposing each to a slightly different perspective on the world, etc.