We read all of this thread with great interest, as our 14 yr. old is starting PADI lessons this coming weekend. Clearly, there isn't "one right answer." There certainly are concerns about the unknown physical effects of diving on developing bones, as well as the emotional maturity of kids (and some adults) to handle emergency situations. As others have pointed out, there are risks in much of what our youngsters do, including riding bicycles and driving automobiles. (We're already telling our son that driving cars isn't a "right" one automatically gets when you turn 16, it's a priviledge that has to be "earned" by showing good judgement and responsibility, because it's an activity that can harm himself and others. In a way, so is scuba diving.)
To us, a major positive about junior diving is that we can do more together as a family. In this day and age, teens generally prefer "couch potato" video games and peer interactions, but as parents, we think family times are important, too. We feel that it is safer for our child to be diving with us, following strict depth limits, than off on his own (on land or in the water) being exposed to who-knows-what. Ultimately, we know that we can't control everything, but we hope that by setting good examples of thoughtful behavior, we can teach our children well.
We've been certified since the early '80's, and that was before much "proportioned" equipment was available for smaller divers. (As a 5'4", 110# female, I am very aware of the potential for injury while carrying the heavy equipment. Our son is roughly the same size, so we think he is capable of managing now, although it will still be work.) We have gone on a few Caribbean vacations where the hotels offered resort courses, but two years ago was the first time our son said HE wanted to try diving. We aren't pushing him, although we acknowledge that if he'd never seen us dive, he probably wouldn't be as interested in the sport.
We've explained that there's far more involved than just jumping in the water with a tank on his back, and how important it is to understand the science and some of the risks behind diving. Very young children can't possibly grasp that, they only see the "fun."
As tempting as it would be to let our child get certified in warm water, without all of the cumbersome wetsuit gear, we want to be sure that he can handle some less-than-ideal conditions. We also realize that he's more apt to pay attention when class work is being done locally, versus in a nice resort area where "kids wish they were outside doing something else." Nobody wants to "give up" their vacation days to be in "school."
We've let our son breathe off our octopus in the local pool, and he's practiced being able to clear a flooded mask,etc. He's read the PADI coursebook, and has a strong understanding of science and math, so even the repetitive dive tables seem easy for him to deal with. We suspect he's going to be bored in the actual class, but if he passes, then we will look forward to our next family trip with even more enthusiasm. As parents, though, we're prepared to set cautious limits for his scuba explorations. If he doesn't pass, that's okay, too, because HE has to be ready to take on the responsibilities for himself first, before he can be a dive buddy for anyone else.