You may notice that your baby starts to become more clingy as they get older, crying if you leave the room for only a few seconds or needing to be held by you all of the time. Separation anxiety is a normal stage of psychological development for babies that usually starts at some point between 8 and 18 months old. Separation anxiety is actually a good sign of an emotionally healthy child, however it can leave many parents wondering if they have done something wrong and somehow created an unconfident baby.