"Babies are soft. Anyone looking at them can see the tender, fragile skin and know it for the rose-leaf softness that invites a finger's touch. But when you live with them and love them, you feel the softness going inward, the round-cheeked flesh wobbly as custard, the boneless splay of the tiny hands. Their joints are melted rubber, and even when you kiss them hard, in the passion of loving their existence, your lips sink down and seem never to find bone. Holding them against you, they melt and mold, as though they might at any moment flow back into your body.
But from the very start, there is that small streak of steel within each child. That thing that says "I am," and forms the core of personality.
In the second year, the bone hardens and the child stands upright, skull wide and solid, a helmet protecting the softness within. And "I am" grows, too. Looking at them, you can almost see it, sturdy as heartwood, glowing through the translucent flesh.
The bones of the face emerge at six, and the soul within is fixed at seven. The process of encapsulation goes on, to reach its peak in the glossy shell of adolescence, when all softness then is hidden under the nacreous layers of the multiple new personalities that teenagers try on to guard themselves.
In the next years, the hardening spreads from the center, as one finds and fixes the facets of the soul, until "I am" is set, delicate and detailed as an insect in amber."
~ Diana Gabaldon