This proposal goes both too far and not far enough if you want to allow parents to certify that a child is to have access to an adult site. E-mail is too easy to fake. The rest of the proposal seriously erodes privacy.

A simpler solution would be to allow some third-party servers to establish an RSA-secured site that would publish it's PGP public key and then require both a current credit card number and expiration date, Social Security number and a valid driver's liscense number (three options are less likely to be available to the child). The site would then verify the validity of all three and allow a PGP parental signature to be placed on the site along with a code name or number.

When a parent wished to give permission to an adult site for his or her child, the parent could give the site the name of the server and the code to extract the PGP signature along with his or her public key. Using the public key, the server could quickly verify if the signature was valid and decide based on that.

This gives complete control to the parent without compromising anyone's security or privacy, without involving a large government oversight group. The government's role would be a random, annual audit of each third-party server's practices. I would expect the government to require each such server to register with the FTC.

I think this would satisfy most authoritarians, liberals, conservatives and libertarians.

I don't know if you considered this kind of proposal, but, if I had my druthers, this is the one I would most prefer. I am completely opposed to the one you propose, but others are more likely to deal with that one's arrangment.