No ID required at airports for children??

This Christmas will be my first time flying with my son. I'm not looking for a debate on whether it's safe to fly right now, so please save that for a COVID-centered post. Anyway, I noticed while doing some planning that my son will not need any form of ID (he's only going to be 13 months by then so it would be a birth certificate). I'm flying through United Airlines, I'm not sure if other airlines have different policies. Obviously he's my child and I don't have any problem with him not needing ID but...it makes me think just how easy it makes it to traffic children! No form of ID needed? How do they know he's my kid? It makes me a little bit frightened. Wouldn't it be easy to change policy to require a birth certificate or something? What are your thoughts?