Linked to the deaths of 3 kids that I know of, possibly more since, and definitely the traumatizing and poor mental health of far, far more.
Don't train kids. Raise them.
This book openly compares children to soldiers and includes stories of just how awfully the authors raised their own children, such as the pulling of a baby's hair for biting too hard when suckling its mother, and justifies this with religion rather than the scientific evidence which has consistently proven that raising your child like this is simply awful for the child.