I have no respect for a decision to carry a Down syndrome fetus to term. On the contrary, I consider it unethical, irresponsible and selfish.
Unfortunately, many staunchly pro-choice liberals go out of their way to express admiration for pregnant women who continue a pregnancy knowing that they carry a severely disabled fetus. Many have falsely convinced themselves that being pro-choice requires respect for every reproductive choice and precludes passing judgment based on the choices others make.
But being pro-choice has never meant that. Many pro-choice people openly oppose abortion on moral grounds. Many would not be comfortable having an abortion themselves. Being pro-choice means supporting the legal right to abortion so that others can make choices according to their own circumstances and moral code. It means not legislating private morality. It does not mean relinquishing moral opinions.
Suppose you are a Catholic who believes that the embryo gets a soul at conception, but, being a reasonable and tolerant person, you realize that others may not share your beliefs and that there is no objective evidence that you are right and they are wrong, so you support keeping abortion legal. I may disagree with your belief (and consider it wacky), but in the mundane deeds - which are what ultimately matters to me - I will gladly be your ally and work with you and respect you. I wouldn't think of saying that you are not really pro-choice just because you see abortion as immoral. But that has to work both ways. As long as I am not legally denying anyone the right to carry a pregnancy to term, I will not allow anyone to question my pro-choice credentials simply because I challenge the morality of those decisions.
So please no bullshit about respecting whatever choice a woman makes. Now let's see, rationally, what happens when a woman chooses to continue the pregnancy despite the bad news.
First and most obviously, she will knowingly impose unnecessary suffering to a human being. Yes, reality does exist and disabled people suffer. And yes, mental retardation is suffering, even if the victim is not fully aware of it. You would probably not argue that advanced Alzheimer's patients do not suffer, would you? (Incidentally, early-onset Alzheimer's is common in persons with Down syndrome.)
And no, the oft-heard argument that most living sufferers prefer to be alive is not relevant to abortion. It retroactively imputes the mind of a formed person to a non-sentient fetus, which is nonsense. The fetus has no meaningful preferences, and that is true whether it is healthy or deformed. "You would rather I didn't exist" is a fallacious emotional appeal that could be used against contraception and abstinence just as much as against abortion. You think sex before marriage is wrong? Oh, so you wish Sarah Palin's oldest son - the one about to be deployed in Iraq - didn't exist!
By the way, if you want to be noble and raise a disabled child, why don't you adopt one? That's a decision I would admire (provided you considered the issue in the next paragraph and ensured there would be no harm, or at least there would be a net benefit). No creating new suffering, but alleviating the already existing.
Second problem arises if there are other children in the family. A disabled child needs more attention than a healthy one. (I assume that the mother who decided to have the child has also accepted the responsibility of giving the child the care it needs.) It is often hard to take proper care of healthy children. With a disabled child, the healthy ones can become neglected. (Of course, the same - perhaps even grater - danger exists for any disabled child already in the family.) Noble attitude to a fetus at 16 weeks of gestation is a very poor justification for unfairness to a toddler.
The third problem affects the broader society. Down syndrome babies become Down syndrome children and, thanks to modern medicine, eventually Down syndrome adults. Most of them are never able to live fully on their own and all of them require extra resources for health care, education, and other support. As our society ages, we will feel an ever greater shortage of caregivers. Every new person needing a caregiver will compete with others for a precious resource. At the same time, more and more women are having children after age 35, so more and more conceptions result in trisomy 21. Currently, the number of people with Down syndrome and other similarly severe genetic defects is too small to require a significant share of total resources, but if the anti-abortion crusaders have their way, the number could easily grow fivefold in a generation.
Testing for Down syndrome is a routine part of prenatal care, especially in older mothers, and when it is diagnosed, over 90% of women choose abortion. Anti-abortion advocacy would imply that those 90% are making the wrong moral choice. We need more voices questioning the decisions of the remaining ten percent.