The US has no compulsory ID. Parents are not even required to register births; medical professionals are, though, and a lot of things become challenging without a birth certificate, so I imagine the vast majority of births are registered. It's only within the past few decades that children were registered with social security at birth, instead of later. My siblings and I were only registered when it became necessary to get a credit on my parents's taxes; my parents were registered when they began to seek employment.