Posts Tagged ‘preimplantation genetic diagnosis’

PGD: a stem cell reconciliation?

January 28, 2012

When a man and a woman make love and give life together to a new person, this is a beautiful event. The love act is creative in every sense of the word, but most especially because of this: the two lovers have contributed to an eternally procreative art project that has been blooming on our planet for a very long time.

Whoever or whatever the Creator of this life process is, or is up to, is not my question to explore just now, although I have made some decisions in my belief about that question. I merely want to point out a fact or two about the process through which we humans have come to have our individual existences.

Fact #1 is this: you, as a human person, have 46 chromosomes.

2.) 23 of your chromosomes were passed to you from your father; the other 23 came from your mother.

3.) These chromosomes, or coded genetic programs, establish a biological framework for your physical existence and life-long development.

4.) Since the unique man who is your father paired his 23 with the 23 chromosomes within that unique woman who is your mother, then you yourself are unique. You–your particular combination of 46 chromosomes– had never existed before. So you are a unique creation. Congratulations. There has never been another “you”; nor will there ever be.

These days, microbiologists can husband this human-making process in a laboratory. Believe it or not. It is not as much fun–not nearly as satisfying– as making babies the time-tested Adam and Eve hubba hubba way. But hey, this test-tube thing is happening. This is what humans, in their quest for improvement, do. The scientific rationale for in vitro fertilization is this: some couples have not been able to conceive a child naturally, and so they can get  clinical help to bridge that fertility gap.    After obtaining sperm from a man, and an egg from a woman, the microbiologist combines them (in the famous “test tube”), and a new human is begun.

Here’s where the scientific work, and the ethical discussion surrounding it, becomes a breeding ground for controversy. My opinion is: Since a unique, never-before-existing 46-chromosome arrangement is manifested in space and time, soon to be flesh and blood–no matter how the conception was facilitated– we have a new human being our hands. This is creation, by which we men and women participate with the original Creator. And it is serious business, because a person’s life–and entire lifetime development–is at stake. There are great–dare I say “sacred” responsibilities present here.

Well, simple enough, really. Not. The further you climb on the tree of knowledge (or the double-helix of DNA), the more complex do your choices become. This is part of what Moses was getting at when he wrote Genesis. But I’ll not go there now, as if I could. Anyway,  as it turns out, there is another reason that scientists have for working with in vitro embryos. Some of them are leftovers.

Yes, Virginia, the outcome of the test-tube baby boom is that we have thousands, possibly millions, of little embryos suspended in cold-storage, probably at about -196º C.  Most of them will never be implanted in a mother’s womb. Some of them will be, but not all. So guess what–another thing that’s happening is this: the key to medical progress is contained deep within the very life process itself, beginning with its earliest stage, the embryo. These frozen embryos. So the scientific community wants to call these microscopic potentialities into the service of mankind–involuntarily, of course–by harvesting their totipotent genetic characteristics to improve the health of living persons.These little ones are the source for the famous “embryonic stem cell” lines that are cultured in petri dishes in laboratories all over the world.

So then the question becomes, quite infamously: Are we, as a human race of civilized persons, going to allow these suspended potential kids to be sacrificed, for the sake of medical progress, so that already-living persons can have qualitatively better lives?

We don’t want to kill those 46-chromosome-bearing new creations just for the sake of heartlessly improving our own already-established lives. That would be, in the biblical sense, not unlike child sacrifice. Civilized people don’t do that, do we?

Well guess what. I heard on the radio yesterday that microbiologists have developed a technique for obtaining individual embryonic stem cells from a 3-day embryo (in what’s called the “cleavage” stage of fetal development) without killing the embryo. The procedure is called PGD, which stands for pre-implantation diagnosis. In it, the microbiologist extracts a single cell  from the 8-cell embryo, leaving the embryo virtually intact for further development and life.

The PGD single-cell extraction procedure has been widely used all over the world. According Dr. Robert Lanza, in his statement during an interview with Ira Flatow on ScienceFriday (NPR), its use is dependable. Dr. Lanza’s research pertains to stem cell therapy for improved eyesight in patients who have suffered macular degeneration.

But what caught my pro-life ear was Dr. Lanza’s mention of this technique for obtaining totipotent embryonic stem cells without killing the fetus. The little guy gives up a single cell, then moves on to further development. Assuming the best, maybe its a little like giving blood.

A little further reading brought me to: and this explanation: “After three days in culture, the embryos typically reach the eight–cell stage. One to two cells are removed from each embryo on day three and analyzed…”

The extracted cell ia generally used for a genetic assessment of the embryo, so that parents, assisted by the scientists and doctors, can make choices about which of the embryos to choose for implantation in the mother’s womb. This is another controversial development in the can-of-DNA-worms that constitutes genetic research and practices–“designer babies,” and so and so on…

But my interest in this procedure revolves around its potential as a reconciliation between the value that we pro-lifers place on embryonic sanctity, and scientific use of surplus embryos without wholesale killing of them. A little more googling brought me to more info, from a fertility clinic in Houston, where I found this (emphasis mine):

“Preimplantation genetics can be performed in vitro at any of the following developmental stages, the zygote (day 1), cleavage stage (day 3) or blastocyst (day 5). At each of these stages, cell(s) are removed from the embryo for genetic testing in special laboratories. This does not appear to harm the ongoing development of the embryo with over 1000 healthy babies born worldwide after preimplantation genetic screening. However, an insufficient number of babies have been born to confirm that the procedure is completely without risk.

So now I’m wondering: Does this change, at all, the debate between pro-life opponents of embryonic stem-cell research, and the researchers whose microscope sights are trained on all those frozen surplus embryos?

Glass Chimera