One of Facebook's policies is that you have to be age 13 older to gain access to our site. That's because our view is that our site is designed for people who are above that age. So we take a number of different steps to prevent children, including ages 12 and 8, as you mentioned, from gaining access to the site.
Those tools aren't perfect. One of the things we do is we delete the accounts of children under 13 once we've verified that they in fact belong to people who are under 13. If you go into our help centre, you can find information on how to contact us. We would obviously want to verify that you are the parent of the person who created the account before doing so.