Your baby's flinch when his sister screams feels alarming, and you want a clear answer about whether it harms him. A startled reaction is usually a normal reflex, not a sign of lasting damage, but ...

The Moro reflex is a startle response in babies that makes their arms extend and retract. Newborns grow out of the Moro reflex within the first two months of life. The absence or extreme presence of ...