" The ever-shifting but almost perennially uneven balance of affection and obligation between parent and child is one of life's deepest and most bittersweet experiences. And it illustrates how imprecise the genes can be in turning on and off our emotional spigots. Though there seems to be no good Darwinian reason to spend time and energy on an old, dying father, few of us would, or could, turn our backs. The stubborn core of familial love persists beyond its evolutionary usefulness. Most of us, presumably, are glad for this crudeness of genetic control- although, of course, there's no way of knowing what our opinion would be if the controls were more precise. "

― Robert Wright