Since statistically this is more often the case when small children are involved, we give preference to homes with mature adults. On the other hand, I can't imagine a child growing up without animal companions. This is a disillusioning encounter, offset only by the numerous photos we get of toddlers and bunnies from parents who have have cared enough to work things out in spite of the inconvenience. These parents are giving their children more than a collection of toys. By placing value on relationships with living things, they are laying the groundwork for one of the few things in life that is truly permanent.
Material things come and go.
And what lives on in the child who has experienced such a relationship is the capacity to care. This is alive. This is valuable. You don't throw it away.