"Honour thy father and thy mother" - what do grown children owe their aged parents?

What do grown children owe their aged parents? This article describes some visions on filial obligation, current in modern ethical theory, and evaluates them from a theological perspective. Why should children help their parents? Is it out of gratitude, friendship, because they are indebted to them, or is it simply because they are their parents? And what kind of assistance may parents justly expect their children to offer them? The article presents and evaluates four theories of filial obligation. Biblical texts seem to support the so called debt theory which argues that children are in debt to their parents and that they are repaying them with their care what they owe to them. A variant of the debt theory is the model of gratitude. Both theories go astray by supposing that the mutuality in parent-child relationship is marked by reciprocity. The friendship approach argues that there are many things that children ought to do for their parents, but that it is inappropriate and misleading to describe them as things "owed". Parents' voluntary sacrifices tend to create love or "friendship", rather than creating "debts" to be "repaid". But friendship does not describe sufficiently the filial reality neither: one can end friendships, but not parenthood. And parents can never be the equals of their children, as friends can be. Apparently, the most satisfactory theory is the special goods theory, which underlines the special relationship between parent and child. That means also that the goods of parenting are unique in kind. Accordingly, adult children should provide frail and dependent parents with something that they will not get otherwise. This approach can get theological support and a faith inspired horizon by interpreting filial relationships in an eschatological perspective and considering them as a divine mandate.