Our initial online searches revealed no mention of this matter. Even the first tier of Skype tech support did not come up with it as a possibility. Neither could I find any mention of it in Skype's or . A third-party on How to Use Skype Safely correctly notes: "By default, Skype restricts the privacy settings of users under 16 years old to ensure maximum protection." However, it does not elaborate on what those restrictions are. A similar article from came the closest to nailing it, adding: "Calls and chats are reserved to those on their (minors') contact list."
In any case, if you can easily bypass the restriction by changing your birthdate (as a determined minor might well do), it doesn't seem to offer much protection.