What was your religious upbringing, and why do you believe you never responded to it, Clydey?
My mother isn't insanely religious, but she was pretty devout. I really don't know why I didn't take to it. In all honesty, I don't think I ever really believed in any of it, even when I was an altar boy.
A lot of things about the brain aren't fully understood, particularly intelligence. Heck, intelligence hasn't even really been defined.
I should probably have responded to your post tomorrow, since it's past 2am and my brain is knackered.