The controversiality is exactly that in the Real World(TM) it's possible to either anonymously verify a certain age (by trivial visual inspection in most cases)

The controversiality is exactly that in the Real World(TM) it's possible to either anonymously verify a certain age (by trivial visual inspection in most cases) or handle it in a way that does not require the potential storage of information (Handing - or better, showing - a cashier your ID doesn't mean they can take a photo of it and store for however many months) Meanwhile, back on Teh Interwebz, the only way we have right now of verifying age is by uploading photos, or equivalent information, of the identification document, which could be intercepted, stored, or otherwise pilfered with no further indication. I think there was someone proposing a cryptography-based way of proving "yes, this visitor has access to a non-minor identity", but that requires some sort of government (or similar) service that could also log incidental information, and would require some sort of digital identity service (for example gov.br here in Brazil): Service generates a random token, user gives token to identity service using their authentication, identity service replies with the token signed with a key whose public part the website knows. This would be "better", in the sense of you don't have to provide any actual identifying information to arbitrary websites, but very bad because now the government can log all age-check attempts. There is probably some more complicated solution to that, but it goes beyond me. In the meantime, my opinion is that online age checks are dumb, easily bypassed, and possibly dangerous. Until we find a proper solution, just educate yo kids properly. Friendly reminder that criminals don't have to obey laws, so actually dangerous websites (be it just psychologically, like I don't know, gore, to actual illegal things) won't be so kind as to implement an age check themselves anyways. If you want the minor you're responsible over to not view harmful content, teach them about the internet and have a healthy relationship with them so they trust you in the eventuality they see something disturbing.