I just checked Hotmail and they have some options that might help you. In the "Filters and reporting" option you can set the junk mail filter to "Exclusive". This option will send all email to the junk mail folder unless the email address is in your contacts or is a safe sender (which you control). Lastly there is an option to delete all email that goes into the junk mail folder immediately, so the child will not have to see the email.
I haven't tried this myself but it seems to fit your requirements....assuming it works.
Slashdot Mirror
I just checked Hotmail and they have some options that might help you. In the "Filters and reporting" option you can set the junk mail filter to "Exclusive". This option will send all email to the junk mail folder unless the email address is in your contacts or is a safe sender (which you control). Lastly there is an option to delete all email that goes into the junk mail folder immediately, so the child will not have to see the email. I haven't tried this myself but it seems to fit your requirements....assuming it works.