It's not like there was no brain activity and machines were merely keeping TS alive. She was starved to death and survived for days after been taken off any life support machines. (Not a kind sort of death!) At what point do you decide that that spectrum of TS non-valuable life form has begun? What if others close to the person (or perhaps even the person themselves!) value their life, while the next person decides it would be more convenient if those kind of people were not taking up valuable hospital space and resources since they are not living quality life and are going somewhere better anyway?
I guess my argument is that whether someone like TS lives or dies, or a fetus at whatever stage lives or dies, someone is always imposing their belief on the general population. Unless you believe there is a higher moral authority like God, it really boils down to who is in the position of the most power to impose their belief.
TS was an interesting case. You're right, those in power get to impose their beliefs. In Terry's case, it was a matter of either her husband or her parents choosing whether or not she was going to be fed manually and somehow keep her alive.
From a Christian perspective, the Bible makes it clear that a person who witnesses a murder and doesn't seek to intervene is as guilty as the murderer.
I think if you're going in that direction, then we have to ask if aborting the baby is murder.
The answer, according to the Jews in the OT, seems to be no.
There is specifically a law in the OT regarding the punishment of a man who attacks a woman with the intent of causing her to miscarry. If he succeeds in causing her to miscarry, the law for intentional murder is supposed to be death, isn't it, according to the Ten Commandments and other similar passages?
It should be, if the baby is a fully human life = murder. And this action is essentially a planned abortion (against the mother's will).
But no, this man who intentionally murdered this woman's baby out of malice is... fined 50 shekels (or some similar fee).
The price is paid to the baby's father, since I think only he could own property or was officially the owner of the baby.
So it's pretty clear the unborn child was not equitable in Old Testament law to a live baby, because the punishment for "murder" under the law is not imposed in this situation.
It sounds like the Jews had the same issue that we have when trying to determine the value of a human life before birth, and they chose to approach it pragmatically.