Want to add another email in Join Form

i have made a kids social network where is want one more email when joining the site.

The email will be Parent / Guardian Email: ____________________

Is there any possibility to add another email in the join page or some other thing where guardian will know that this boy has joined this website.

Kindly inform me.

Thanks

I think I understand the idea; the child joining the site would have to put in their guardian/parent email address.  The profile would not be active until the parent responded to the email.  However, what is to prevent the child from using some free email account and bypassing their parent?  You might want to think of another way to verify.