Parents! Great Stuff On Kids Headphones!
I don't do this very often...heck, I don't think I've ever done it, but in this case I'm going to heartily recommend an article written on headphones from another publication.
Lauren Dragen and Brent Butterworth have recently published and excellent article on volume limiting headphones for kids. Parents should rightly be concerned for their children's hearing health, and there's no doubt that lots of kids are turning the volume up far too loud in their listening. Lauren and Brent go to great lengths in this review to educate parents on the subject; measure the headphones under consideration; test them with focus groups of youngsters; advise parents on best practices for children's safe listening; and make product recommendations.
The only thing I'd add to their piece, and it's not likely to be terribly effective, is that loud music doesn't sound as good as music at reasonable listening levels. Giving kids a little education on that point might just help a bit in keeping them satisfied at moderate listening levels.
At any rate, if you're thinking of giving a youngster a headphone this gift giving season, I highly recommend The Wirecutter's, "The Best Kids Headphones"