Parenting

What good parent hasn't fallen asleep in a child's bed, or spent half a night awake comforting a nightmare?  I've been thinking about why we do it--put ourselves out for our children in strenuous and exhausting ways?  I am pretty sure that it is because children are our long-term-care policies, and if we don't fuck them up too much, they will change our diapers when we get old.