Suppose you were misguidedly to give your own child poison. The fact that you might think the poison you were administering was good for your child, the fact that you might have gone to a lot of trouble to obtain this poison, and that if it were not for all your efforts your child would not even been there to be offered it, none of this would give you a right to administer the poison—at most, it would only make you less culpable when the child died.

• Nicholas Humphrey