Teratomas

William Saletan at Slate had an article on these strange things a while back; Ramesh Ponnuru followed up with two articles at TCS. Teratomas clearly (to me) have no moral status, but as Saletan noted, they raise the question of just how dysfunctional does an otherwise biologically human organism have to be before we can treat him/her/it as a thing, rather than a person. This question has actually come up before. Remember Terry Schiavo? At the beginning of life the argument is over the meaning of extreme developmental dysfunction. At the end of life the argument is over extreme brain dysfunction. What I find most discomforting is that we've don't know of any clear biological dividing line. At least in the abortion debate, biology clearly (to me) provides the dividing line of conception.