Online age checks are on the rise in the U.S. and elsewhere, asking people for IDs or face scans to prove they are over 18 or 21 or even 13. To proponents, they're a tool to keep children away from adult websites and other material that might be harmful to them.

But opponents see a worrisome trend toward a less secure, less private and less free internet, where people can be denied access not just to pornography but news, health information and the ability to speak openly and anonymously.

"I think that many of these laws come from a place of good intentions," said Jennifer Huddleston, a senior technology policy fellow at the Cato Institute, a libertarian think tank. "Certainly we all want to protect young people from harmful content before they're ready to see it."

More than 20 states h

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