Reply #9: Liking babies is indeed programmed into our DNA.

[Kurt_and_Hunter]

And not considering newborns to be babies also seems programmed into us.

Some mothers have an ingrained reaction of hostility to their newborn that fades over time. A mother is supposed to be emotionally able to walk away from a deformed newborn. I suspect that fierce conflict between instinct and socialization accounts for some of post-partum depression.

(Anyone who has seen a lot of mother cats with her newborns is familiar with the harsh calculus that goes on sometimes.)

I have never read about an ancient society that did not "expose" certain newborn infants. (Leaving them outside to die.) In the Old Testament a baby under one moth old has an entirely different legal status. And, as mentioned in the OP, most societies have had some christening process.

Here's another thought experiment. Catholics used to believe that unbaptized babies went to limbo or hell or someplace outside the grace of God... dogma changes, but the point is that they didn't go to heaven. (Until the 1960s, I think)

To get into heaven you had to be baptized.

Now then, when was a baby baptized? Obviously at the moment of birth, since its soul was in peril!!!

But that's not the case at all. Babies were, and are baptized some period after birth. That reflects what seems to be our instinctual idea that new borns grow into person-hood during the early stages of post-natal life.