Exactly. Babies cry because they're new to the world. They have not yet grown the moderating influence of context provided by experience. Every baby is unique,

Exactly. Babies cry because they're new to the world. They have not yet grown the moderating influence of context provided by experience. Every baby is unique, with a different emotional balance. A big chunk of parenting is figuring your kids out, and balancing that with the set of experiences they need to have in order to grow. Many of those experiences are painful, which means you also need to figure out the balance of "let them cry" and "comfort them", which also changes drastically over time. That's where having both parents really matters, as the tension between them is essential in finding that balance.