Taken to its logical extreme, you could argue that sometimes it is advantageous for a society to harvest the organs of a healthy person, so that multiple people can have their lives extended through transplantation. Eugenics can also be argued for by saying that there's a net benefit to society.

One argument against this is based on the philosophical concept of a Veil of Ignorance[1]. We should create the rules of society as if we don't already know what our position in society will be. No one wants to live in a society where they could be randomly selected for organ harvesting, for example.

[1] http://en.wikipedia.org/wiki/Veil_of_ignorance