We have all seen this moment countless times: a baby enters the world and bursts into tears. It is so common that we rarely stop to wonder why it happens. Why do newborns cry instantly after birth?

Few moments melt a parent's heart quite like watching a sleeping baby suddenly break into a smile. It often happens without warning, a tiny grin appears, lingers for a few seconds and disappears just ...

Add Yahoo as a preferred source to see more of our stories on Google. Witnessing happiness on a child's face is everything that is good in the world. It's what we live for as parents, caregivers, ...