This is emotive. How can it not be? There are those of you with NT children, who can conceptualise the argument. Then there are those of us who know that it is OUR children who are being made 'expendable' or even, worse, illegitimate.
Posters like Kalskirata, sevenfold, 2old2bemum, lougle, Sanctimoanyarse (possibly more, I only pick those names because I know that they are all posters who have a child who is seen as 'damaged goods' by some 
) read these threads, then they realise that no matter how much effort they plough in to making every day count for their child, that there are those who think that every one of those days is wasted.
SolidgoldBrass says "Thing is, I think this particular debate is a bit spurious as it is so very unlikely that a baby will be born with severe disabilities that are a) obvious at the moment of birth and b) not obvious beforehand. I'm aware that sometimes birth trauma can cause severe brain damage but that wouldn't necessarily be instantly clear.
So if (for instance) a woman was carrying a foetus that was massively encephalic, had Harlequin syndrome or some other problem that would mean its life post birth would be very short and possibly very painful, she would most likely be aware of this before the child was born and able to opt to terminate the pregnancy."
It happens more often than you'd like to think. I know personally one woman who had been given low risk for a condition routinely screened for, gave birth and her baby was admitted to scbu for a bit of low sugar. She found out about her DD's diagnosis when a consultant saw her and started talking about her child's 'complications' (she thought - low blood sugar) and it dawned on her that no one had actually told her about her baby having a genetic condition. Her baby was affected by the condition enough to need two or three surgeries.
I myself was scanned relatively frequently in pregnancy for various reasons. No abnormality detected. Induced on the day before my due date as showing small for dates. Wasn't allowed home until a SpR reviewed DD. I demanded to know why, so a junior doc confessed that a midwife thought DD looked 'Downs syndrome'. Now, I was a nurse who had worked on SCBU. I checked DD over...no sandal wedge toe, no irregular creasing, etc., so I was unsurprised when the SpR said 'nahh just been squashed down a birth canal'. Now, 6 years on, DD1 goes to special school, GDD, LD, epilepsy and dysmorphic features. The midwife wasn't as wrong as they thought.
There is a fantastic poster on the SN boards whose threads started off in bereavement. She gave birth to a beautiful baby, then was told that she would die. No prior warning at all. Well that baby has stuck her fingers up to the medical profession and is still going - good girl.
For me, it's that slippery slope. Those of you who are for assisted death. It starts out that if someone can decide they want to die, they should be helped to do it as easily as possible. Then, people think 'ah, but so and so would want to die, he/she just can't tell us...before long, you'll have people making judgements on someone elses quality of life.
As someone said before, what changes a foetus into a baby? Going down a birth canal? No...we still call foetuses removed from their 'host' with a caesarean a 'baby' afterwards. So it can't be that. Is it the fact that they are outside?
Doesn't it seem ludicrous that a 34 week baby outside the womb could have more rights than a 40 week foetus in the womb?