Babies aren't capable of suspending what intellect they have in order to force themselves to believe in something that has never shown itself in anything other than slices of burnt toast or funny shaped vegetables. Some adults seem to manage it though.
The story you outlined, about john the baptist leaping for joy in the womb - sounds like indigestion to me. (I have GORD, so I know).
Re the man made construct - plenty of evidence, as outlined in this interesting piece that I remember reading a while back. It sort of alludes to the nascent requirement for parental protection and caring I mentioned earlier: articles.latimes.com/2011/jul/18/opinion/la-oe-thompson-atheism-20110718
Excerpt:
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Like our physiological DNA, the psychological mechanisms behind faith evolved over the eons through natural selection. They helped our ancestors work effectively in small groups and survive and reproduce, traits developed long before recorded history, from foundations deep in our mammalian, primate and African hunter-gatherer past.
For example, we are born with a powerful need for attachment, identified as long ago as the 1940s by psychiatrist John Bowlby and expanded on by psychologist Mary Ainsworth. Individual survival was enhanced by protectors, beginning with our mothers. Attachment is reinforced physiologically through brain chemistry, and we evolved and retain neural networks completely dedicated to it. We easily expand that inborn need for protectors to authority figures of any sort, including religious leaders and, more saliently, gods. God becomes a super parent, able to protect us and care for us even when our more corporeal support systems disappear, through death or distance.
Scientists have so far identified about 20 hard-wired, evolved "adaptations" as the building blocks of religion. Like attachment, they are mechanisms that underlie human interactions: Brain-imaging studies at the National Institutes of Health showed that when test subjects were read statements about religion and asked to agree or disagree, the same brain networks that process human social behavior ? our ability to negotiate relationships with others ? were engaged.
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