This is an interesting question which seems to combine a legal question with a scientific question. The answer to whether it is illegal for minors to possess and use an electronic cigarette is completely dependent upon local law. Chances are, if you see them being sold at a kiosk in the local mall, they are probably not illegal for any age to possess or use yet. That being said, I would not be so quick to dismiss the potential health consequences of tobacco or non-tobacco prodcts when inhaled through these systems. The common element of all these systems is the rapid heating of the liquid into a vapor stream for inhalation. The scientific data on the record are clear about two things: 1) it is not yet clear whether glycerin heated in this manner changes its chemical composition to become harmful over the long term, and 2) any tobacco product when heated releases tobacco-specific nitrosamines "TSNA"s which are the primary carcinogens of tobacco other than the by-products of ordinary smoking. If you Google the term TSNAs, there is extensive discusion of this topic. While I am not a rabid anti-smoker, I am deeply concerned as a parent about how these products normalize the act of inhalation so that, when a "vaper" is ready for a stronger hit, the learned behavior of inhaling is already well-established. Be careful and good luck.