Ethics of Siamese Twins

A while back I looked into how Siamese (or conjoined) twins fit into the legal system. This came back in the news with the birth of the girl with two heads. Sadly, the operation to remove the second head failed and the baby died.

I've seen the legal end of this but what about morals? Former Surgeon General Koop once stated that doctors should attempt to separate all conjoined twins because even if they failed and both twins died, it would be better than living conjoined.

On the other hand, many conjoined twins have lived long, happy lives. Many religions feel conjoined twins with two heads have two souls (but what about twins with one and a half?) Stephen Jay Gould felt that it's impossible to pigeon-hole these cases but unfortunately sometimes that's what the legal system has to do.

Any thoughts?