Set a minimum date of birth

I need to limit user registration on my site to users that are 13 years of age or older. I've created the date of birth field.. however the only filtering options that I have been able to find are past dates, future dates or all dates. How can I accomplish this??

I don't know if this will work for you, but I used SplashR to control access to an alcohol-related website. Simple module that displays either a full page or thickbox splash page with configurable text and links. Configurable per page or per visit, cookie-based. Non-commercial, good support, just works.

Matt