I'm surprised none noted the puny names of the characters. Kuro = black, Shiro = white. A bit lazy.
Other than that, you have the Jehovah Witnesses who refuse blood transfusion, or those wackos who refuses vaccines or other life saving treatments. People who say "this child is in the hands of God. If they're meant to die, so be it, but I won't allow blood/medicine/mechanical parts/surgery in their sacred body for fear they go to Hell...". Yeah, right.
That's why laws are enacted in civilized countries that provide that the well-being of children is absolute. Doctors are not allowed to let a child die because of their parent's belief. Period. If the child's life is in immediate danger, they would seek an urgent decision by a judge, even if it's 2 AM, to take custody away from the parents. And if they make a ruckus, Police is called. If that's all it takes for them to "hate" their kid, then they don't deserve to be parents.