Are they the same at all???

[Wuducynn]

Hmm...I guess I don't think of these twin or twinner yous or mes as such. Consider the possibility that they share the same soul or essence (for those nonreligiously inclined). This is more what I have in mind than genetic potentials. Circumstance and choice determines how much that you is like you.

This is how I see it. Brice put it very well. And some don't have any twins.