I have written a paper on how to do age verification in a completely privacy-preserving way, and it doesn’t even need zero-knowledge proofs:
https://magarshak.com/papers/Personal.pdf
I'm talking about complying with laws, in a privacy-preserving way. It's possible.
Here, I posted it on HN: https://news.ycombinator.com/item?id=48760492
I have written a paper on how to do age verification in a completely privacy-preserving way, and it doesn’t even need zero-knowledge proofs:
https://magarshak.com/papers/Personal.pdf