St. Louis boy, 16, has consensual sex with girlfriend, 14, and tapes it. Shows tape to friends. Gets caught and pleads guilty to public display of explicit sexual material.
A few months later, a new law makes that a charge that can land a person on the sex offenders list -- and the state says the teen's name should be added retroactively. Teen sues to keep himself off the list, and now the case has gone before the Missouri Supremes, who sound like they agree with him.

