The little child with bone cancer is imperfect. The bone cancer shows it. Since he is imperfect, he is a sinner, even though it was foisted on him by his parents.
There is no sin to have cancer. There is no sin at all. Humans created morality, and we decide what is wrong and what is right.
We view the little child with sadness and sympathy, and shower him with more than he would get normally.
Your fairy tale either does nothing or doesn't exist. Same difference.
