Anyway, thanks to Mark Shea for pointing out this good discussion on the truth about euthanasia and physician-assisted suicide.
The notion that certain patients lack worthwhile lives is a judgment which Western law and medical ethics have long rejected and which no civilized society should accept. This is, moreover, no "private" decision. The question whether some citizens (doctors) should be allowed to kill other citizens (patients) is a decision with profound ramifications for the safety and well-being of the whole community, not least its most vulnerable members. The community, rightly, jealously guards its power to decide when human life may lawfully be taken and it has, again rightly, strictly limited those circumstances. The decision to allow doctors to kill patients who consent to have their lives ended is no more "private" a matter than a decision to allow plantation owners to buy and sell slaves who consent to be owned. There are, indeed, few questions which are of greater public import than the question whether to permit VAE/PAS.