In America, parents are expected to apply for a social security number for the kids or we do it as an adult, so the expectation is that everyone has one. This is not the only number that follows you around. I am not sure if this is true in every state, but I know it is in mine.
K-12 School
When a child enters school in this state, they are assigned a state based ID number. Once assigned that number follows that student to any school they attend or work at. Yes, if you are employed by a state K-12 institution your student state ID follow you to that job.
University
I had an interview a year or so back and they asked me about a name I had previously used, which I explained, but then asked how did you even know about that cause it wasn’t on my application or resume. It was explained to me that if you apply at a school and in some instances send your FAFSA there, that it generates for them an ID number and it pulls you up going forward using that. So when they looked me up in the system it brough up a listing and probably matched up my birthdate to say this is the same person. I have been informed that because of my name change before, now with another one, that I would have to provide proof to get this name updated with them.
Big Brother with the Numbers
Big brother may have the watchful eye, but be careful with those numbers. They can definitely trip you up and cause problems. Hopefully you are working with people who know what they ard doing and not people who insist you have to go by what this says. I still get mail and texts for my birth name even though my birth name was never affiliated with my last two residences and my current phone number was never affiliated with that name either.