How do I restrict registration to age 18 and up?

[MS007]

We currently have our registration process set to deny applicants under 13 automatically...how can I change it to deny applicants under age 18 automatically?

Thanks for any help!

[Zachery]

That is not currently possible with the default software and would require a modification.

[Alfa1]

There is a hack available that blocks all underage users, but it will block search engines as well.
A possibility would be to do a search for all underage users once a month and ban them.