@DebraDownSouth:
And to answer your question, I had Rottweilers, chow, rescues all the tiem my child was growing up. Yes, I had time. Active children do not need you supervising them 24/7. Children need alone creative time, naps (thank goodness) and in reality, my child helped feed and train the dogs from the time she was about 4. Dear spirits my 125 pound rottweiler hit the floor in a down faster for her than ever for me. And if you don't have time to train your dog and raise a child, don't get a dog or learn better time management. I had a friend who had a child with CP. Training her dog was her "me time" relaxation.
It is about commitment. And I can think of nothing more critical than dealing with a dog who is child aggressive. and I can think of nothing more irresponsible than simply choosing to try to isolate the dog from children when you have a child of your own. Do a web search for kids bit by neighbors dogs. You think you can't watch your own child 24/7== try watching the world. Which goes back to the beginning– condition the dog to see kids in a positive light and in that BLINK moment, you have upped your chances of a good outcome. I cannot even believe anyone could argue with that. So now I am truly done.
The part about it being unrealistic to directly supervise older kids 24/7 is completely accurate. Even younger ones to some extent…because...well, you have to have a shower occasionally, and dishes have to be done eventually. That being said, there are some dogs that just can't be trusted alone with kids, and those dogs can be crated when these situation are necessary. We have one dog like that...she has improved tremendously in the eight years we have had kids, at first she couldn't really be trusted around our toddler even with us in the room....now she is reasonably trustworthy around twin toddlers, but I still don't trust her alone with them. This change in her occurred with natural desensitization to the hubbub of children, time passing, and some concentrated work with her to learn to look to me, when she gets that feeling of "I am overwhelmed". So obviously, if she gets overwhelmed because a toddler falls on her, and I am not there, she doesn't have anyone to turn to. Not fair to her, or the kids.
I don't think there really is an argument to be had here. Both parts of the puzzle are needed here. There needs to be desensitizing training, there needs to be an alternative response behavior trained in the dog, and the dog needs to be put in a 'safe' and comfortable place when she can't be directly supervised with the kids. She will probably be extremely grateful to not be in an overstimulating environment. At first I felt so bad for Ivy when she required a time-out in her crate...but I quickly realized that often she was *asking to get away from the excessive stimulation.
For the OP, I really suggest that if you are committed to keeping this dog in your family, you find a really good trainer/behaviorist who only uses positive methods, and is up to date on the most current topics in dog training and behavioral modification, and pay whatever is necessary (obviously within your means). If you are unsure what trainers would fit the above description, search the internet for 'dog behavioral training' or 'positive reinforcement training'..or even this forum has a TON of threads about what kinds of training is out there. You CAN help this dog fit into your family...but it will take some work, and some committment 
