Parasitic Twin

I learned today about this rather unusual situation where a baby was born with two heads. Oddly enough this was featured on an Oprah episode.
Apparantley this baby was the result of conjoined twins with one developing incompletely only as a head, attached at the base of each of their skulls. Amazingly it was able to survive parasitically receiving all of its blood/oxygen/nutrients from the fully formed body of its twin.
As the fully developed twin was medically compromised by the parasitical twin, the decision was made to remove the attached head in order to allow for the other to survive.
I can understand that they chose between one dying vs both dying, but it's essentially medically sanctioned infancticide. Especially given that they were 10 months old at this point.
I have to say I would be extremely curious to see how the twins would've developed had they been able to survive conjoined and grow and speak.
This reminded me of our debates regarding societally sanctioned infanticide (Dkg who was the author you mentioned?)and of course the question of what it means to be human. I think most people would recoil at the thought of what kind of life the twins would've lived had the other survived, particularly for bodyless one. It's only situations like this though that makes us ask the more difficult questions.
Society currently has no room for situations such as this.. I'm sure if the developed baby was fully healthy , there still would be a call to remove the incompletley developed twin. I'm not sure about this but it seems that even healthy conjoined twins (who could live independently) are slated for separation. I imagine that at some point in time it was perfectly normal for infanticide to occur on healthy conjoined twins simply because of the stigma and the prevailing societal attitudes toward various birth defects.

The author is Peter Singer.
The author is Peter Singer. His FAQ tackles all the big issues right up front. It's worth reading.