Regarding the issue at hand though, determining the quality of life of a fetus is no one's right except the mother's. I do not advocate making this decision for anyone, and explicitly said so in my OP, which I'm pretty sure you haven't read. I have not advocated eliminating the right's of anyone.
And yes, in cases of severe birth defects, I consider having an abortion to be a merciful thing to do. I know it seems unfathomable to you that someone that has to live their life in those cases may not be happy and cheery or take comfort from being the inspiration to normal people everywhere you think they are, but it's very likely true. I can't say for sure that it is in all cases, and that is precisely why I made this thread. I do not make the claim that I have the power to judge someone's quality of life and determine where the line is between what is good and what is bad, and if we're talking about a situation where the person is already born, it's completely irrelevant at that point anyhow. You can't have an abortion once you've given birth. If we're talking about a mother who has been informed that her child will suffer from birth defects if allowed to be born, are you going to tell that mother that she shouldn't consider the quality of life her fetus will have? That she has to choose life regardless of the condition her child will be forced by genetics to live with for the rest of it's life, no matter what their impact on living day-to-day is? I don't advocate that.
In these cases, I think the doctor needs to stress the complications and factors that will affect the child once it's born. It's ultimately the mother who has to make up her mind, but just like you pro-lifers think women should be shown ultrasounds and have invasive unnecessary procedures, women carrying a damaged fetus ought to be made explicitly aware of the consequences of that as well.