In her book, The Fourth Instinct, Arianna Huffington tells of the parents who brought a baby boy home from the hospital, joining an older sibling already in the family.  The four-year-old sister, however, immediately requested to be alone with the little boy.  The parents, though, were afraid that the sister might not handle the little infant with care.  "Why do you want to be alone with him?"  Unsatisfied, the parents ignored the request.  But finally, after persistent requests, the mother agreed; however, she stayed outside within reach should the baby cry.