Use a spam filtering tool to help prevent spam from reaching your child's Inbox.
Since it's impossible to prevent all spam, some may still appear in your child's Inbox. While you can't use a tool to prevent your child from reading spam messages, an Internet monitoring tool can prevent your child from responding to spam.
Monitoring tools allow you to create lists of email addresses your child can receive email from. If your child tries to respond to spam email and the address is not on an "approved" list, your child cannot send a message to that address.