I found this site and was reading this thread when I did a search for "minor's email account" and I want to comment on the reply from Stella on this subject. If child opens an account and lies about their age, there's not much anyone can do to stop them from opening the account. As a parent, I opened a Yahoo! email account for my elementary age daughter and they required me to provide my Yahoo! account and a credit card to prove I was of age and they emailed me at my account as well. This was less than a year ago so it's probably still the way to do it.
On another note, I thought when I setup the minor's account and turned on the SPAM protection that as long as she stayed on kid-friendly sites (Disney, Nickelodean and such) that her account would be safe from porno and such. Wow, was I stupid. I'm not sure what site sold their lists or were hacked into or what, but she got two pornographic emails one day and a few more the next and and quite a few more the next and so on. Luckily, she's not on email that much (yet) and I was on the computer, logged in for her and noticed the subject lines before turning the computer over to her! I forwarded the first one to Yahoo! with full headers and asked for assistance and told them to forward any replies to my parent account. I got a "form letter" reply to her account that basically told me there wasn't anything that could be done put open them and add the person to the SPAM list so they couldn't email her again or go into her account and clean out the garbage before she gets on email. Needless to say, I've changed her password so she can't access it anymore without me looking into it first.