Easier Way to Verify That You Are At Least 13 Years Old

[OS Master]

What I want to do is have a system like phpBB where there are two buttons, one that says "I am at least 13 years old" and "I am under 13 years old".

Right now in order to comply with COPPA I deny registration to anyone under 13. But to do this registering members have to provide their full birthdate. I know some members will feel uneasy doing this, so I wanted to satisfy COPPA and registering members at the same time.

I think this can be achieved with a mod if there isn't one already out there.