There should be no checking in youth hockey, AA and under, 17yo and under.
First of all, kids can't skate well enough to control their bodies in either giving or receiving checks. They just can't, and not at speed. Why USA Hockey doesn't have a skating test requirement to advance to checking levels is beyond sense -- any bozo can get on the ice, minimal skating skills, and throw their body around, injuring other kids, and call it "hockey." And unscrupulous coaches and lazy officials will allow it.
All injuries including brain injuries increase 60% at checking levels, and Canadian studies show that increase stands whether checking starts at 14yo, 12yo or younger. It doesn't matter. By the end of one season, even without a documented concussion, young players show decreased cognitive ability. MRIs show brain changes.
Checking also increases catastrophic spinal injuries.
Kids playing in checking leagues when interviewed express less overall impulse control and more desire to injure other children.
99.99999% of kids playing hockey will never go on to checking adult hockey. Those that do can learn the skill as adults. Right now, NHL and college and juniors are benefiting from the head banging of thousands of children instead of having to teach the skills to a small number who will make them money. It's ridiculous.
Children's hockey and other sports should look vastly different than adult sports. With lower on-ice ability, vast changes and differences in height/weight through puberty, and low impulse control -- and with children's prime goal being academic, and at complete odds with brain injuries, sometimes multiple before leaving high school -- it's perverted the amount of fetishistic enjoyment adults demand out of their children injuring each other and being injured.
Remove checking, allow children and teens to develop skating and stick and game skills fully -- and more kids to stick with the game -- and let the checking to the colleges and pros. How many times do college and juniors get their heads knocked off anyway? All the time. They essentially aren't learning how to check as children, so take it out and teach it when they are making $$$$ to support their CTE.