Aborting Downs Syndrome babies is a moral obligation?

Introduction: I was recently forwarded this news article from a contributor to the Triablogue. In this article, UNC Chapel-Hill biology professor Albert Harris argues,

"In my opinion, the moral thing for older mothers to do is to have amniocentesis, as soon during pregnancy as is safe for the fetus, test whether placental cells have a third chromosome #21, and abort the fetus if it does. The brain is the last organ to become functional."

And why does he say this is the moral thing to do?

"I know somebody who had a child like this, and it ruined their life,"

My translation of what Dr. Harris is saying in light of both comments above is as follows:

"If a physically or mentally defective pre-born child [i.e., a Down Syndrome child] can potentially 'ruin' your life, then you should not only have the moral right to kill it but you are morally obligated to kill it in order to avoid 'ruining' yourself and your immediate family."

So, we should have the right to murder certain types of pre-born babies because they can potentially "ruin" us? In other words, if a pre-born child has the potential to economically and emotionally inconvenience our family, that therefore gives us justification to not only have the right to murder it but makes us morally obligated to do so? Ignoring for the moment that Dr. Harris' conclusion doesn't follow from his premises, let's take the opportunity to reduce his position to absurdity.

A Scenario: My 83 year old grandmother just sustained a Colles fracture after getting into a nasty car wreck that was her fault two weeks ago. She was in the hospital for treatment for the fracture and observation for possible complications associated with cardiac tamponade about a week and had episodes of delirium due to the strong pain medications she was on. As a result of the delirium, she was extremely difficult to interact with, at times was very nasty to my family and at least once that I know of, security was called because she was physically fighting with the nurses. She was out of control. Not to mention that her health is declining overall and the medical bills are becoming very costly and the time needed to care for her is becoming increasingly taxing to my family. In sum, this has been very emotionally and economically inconvenient to my family and while this is taxing our own wallets because my grandmother does not have the money to pay her part, it is also taxing the economic resources provided by the federal government's Medicare system.

Thus, my grandmother has emotionally and economically burdened our family, and could potentially "ruin" our family (or already has according to some) and along with millions of other dear American grandmothers, is taxing the federal healthcare system.

Questions: (1) So, if I am morally obligated to murder my pre-born baby because it can potentially "ruin" me, why stop with pre-born babies? (2) Who gets to decide when they, their family, and even the federal healthcare system have been "ruined" and who gets to objectify for the rest of society what it means to be "ruined"? (3) If an individual or family decides that they have been "ruined", then why is it acceptable to be able to murder a pre-born child to avoid being "ruined" but I can't murder my grandmother for the same reason? (4) What's more, if having a functional brain is the implied criteria for personhood [per Dr. Harris], upon what objective basis is it officially declared "functional"?

Conclusion: If we not only have a moral right but a moral obligation to murder pre-born Down Syndrome babies then it would follow that we have a moral obligation to murder anyone who can potentially "ruin" us via emotional and economic hardship; and that could be just about anybody from our banker and financial planner to our little ole' grandma. Worse yet, the definition of "ruin" at this point is left to the subjective whim of the person being "ruined". And so, if the pre-born physically and mentally defective child will surely bring grief and "ruin" (however that is defined), then why can't I kill grandma too? After all, the only real differences between the pre-born Down Syndrome child and grandma are size, level of development, environment, and degree of dependency. Just as Christians (and most other sane people) would consider it immoral and evil to murder granny because she has a shrinking cerebral cortex and associated intermittent dementia concomitant with her Alzheimer's diagnosis that is severely taxing the family both emotionally and financially, so we would also be unjustified in murdering our pre-born Down Syndrome child because she may "ruin" us financially and emotionally. We don't murder innocent people because they are physically and mentally inconvenient to us; unless of course, you prefer to deny them the usual, legally mandated rights and protections associated with "personhood" that are granted to every other living human being in the U.S. post January 1973 simply in the name of "choice". This isn't the first time the U.S. did this; for the first finely documented instance of this happened to our black neighbors in 1857. How ironic.

In brief sum, the Christian's objective basis for not murdering demented grannies and pre-born babies is ultimately based upon the clear, foundational declarations of Scripture, not upon the inconsistent and autonomous reasoning of sinful, unregenerate men. Take special notice of the first-person pronouns being used by the Holy Spirit through the pen of King David regarding his own human personhood before he was born,

NAU Psalm 139:13-16 For You formed my inward parts; You wove me in my mother's womb. 14 I will give thanks to You, for I am fearfully and wonderfully made; Wonderful are Your works, And my soul knows it very well. 15 My frame was not hidden from You, When I was made in secret, And skillfully wrought in the depths of the earth; 16 Your eyes have seen my unformed substance; And in Your book were all written The days that were ordained for me, When as yet there was not one of them.