“I will prevent disease whenever I can, for prevention is preferable to cure.” So goes the modern Hippocratic Oath (1), solemnly sworn by thousands of doctors every year. But what if prevention of disease encompasses more than a warning? What if it manifests itself before birth?
In vitro fertilization (IVF), a technique that assists otherwise infertile couples to having healthy babies, has been extended to ascertaining genetic health of the babies using preimplantation genetic diagnosis (PGD). Normal IVF procedure entails morphological examination of a few embryos to choose the one most likely for successful implantation; PGD simply extends this into genetics. If taken with a dose of anti-eugenic discretion, PGD has the potential of greatly increasing the quality these children’s lives. As such, it should be adopted into standard procedures for IVF.
The potential for benefit is massive – the embryos could be screened for virtually every possible genetic disease (including Huntington’s disease, sickle cell anemia, and predispositions toward some cancers). So far that makes us able to prevent about six thousand diseases from ever arising in a child’s life (2).
Consider Huntington’s disease. Being a late-onset neurodegenerative disorder, most potential parents do not even know they have the genes for it before they have children. They (and their children, if unlucky), will experience “uncontrolled movements, loss of intellectual faculties, and emotional disturbance” at some point in their lifetime (3). The bearers know they will slowly yet inevitably experience dementia and eventually loss of control. The question is not if the disease will rise. The question is when.
There is no known treatment.
But there is a way out. Huntington’s disease can be screened effortlessly with PGD. Children would not have to live life in fear of a disease that would eventually destroy their consciousness.
At the very least, PGD can be used to “avoid repeated termination of pregnancies following prenatal diagnosis…of genetic disease, which may have serious and long-term effects on women/couples” (4).
Though the benefits are compelling, concerns of potential abuse exist. Popularized in Andrew Niccol’s GATTACA, PGD was thought to be the beginning of a scientific form of eugenics. It was proposed that PGD could be used to select children with exceptional intelligence, height, or otherwise desirable traits (5). Much of this is inconclusive theory. Take, for example, genetic predispositions towards intelligence (6) – though genetics may play a small role in IQ, environmental factors (e.g. upbringing and schooling) conclusively play the leading role (7). Screening children for intelligence is a very abstract fear when taken in context of both genetics and environmental influences.
Gender selection of embryos presents a more realistic issue – PGD does allow selection of the sex of embryos. Though perhaps a problem in other societies, inclination towards any specific gender is insignificant in America (5). Furthermore, sex selection can even play a role in preventing certain gender-linked genetic diseases (8).
As long as parents consider IVF as an option, some embryos are discarded for morphological issues (i.e. those that would preclude successful implantation). Given this protocol is used for IVF, PGD does not contribute to any additionally discarded embryos – just better selected ones.
For this reason, PGD should be implemented for couples who choose IVF through necessity. PGD contributes no dilemma greater than those already presented through IVF, so to maximize the benefit of children conceived thus, genetic screening should be applied.
For parents with high risk of passing on a debilitating genetic disease, perhaps an option of PGD should be offered if genetic testing of parents necessitates it. The question funnels itself to this: if four viable embryos are in a dish and probability says three have Huntington’s disease, why leave the scenario to chance?
It must be remembered, though, that “It’s not about designer babies, it’s just helping people to have normal, healthy children” (4). Keeping that ethical medium in mind, doctors have a responsibility of preventing arbitrary PGD uses. Parents must have a sound basis of needing PGD so the constructive technique will not be implemented as a mere cosmetic – as opposed to preventative – measure.
Sources:
1. http://www.pbs.org/wgbh/nova/doctors/oath_modern.html
2. http://www.guardian.co.uk/news/2006/jun/19/topstories3.genetics
3. http://www.ninds.nih.gov/disorders/huntington/huntington.htm
4. http://hea.sagepub.com/content/14/1/41.full.pdf
5. http://www.time.com/time/printout/0,8816,989987,00.html
6. http://www.sciencedaily.com/releases/2006/04/060427161424.htm
7. http://www.associatedcontent.com/article/2398820/epigenetics_nature_versus_nurture_is.html
1 comment:
Firstly, I would like to make a quick comment on your statement that "PGD does not contribute to any additionally discarded embryos – just better selected ones." Surely, in a factual sense, this is not true as there will be a greater total number of embryos being disposed of. Instead of solely embryos with morphological issues being disposed of, embryos with genetically inherited disorders or certain potentially dangerous gene sequences will also be discarded. While I personally do not view the embryos as human lives, and support the use of PGD, some may consider the discarding of these embryos as an unnecessary creation and, in turn, destruction of a potential life. Then again, PGD should in principal appeal to those who would ever make such an argument, as the screening process will minimize the number of abortions carried out at a later stage of pregnancy (which is arguably much worse than discarding a pre-implanted embryo).
Moving on to the idea that PGD will be able to prevent and eliminate certain diseases - What if we were to take the idea of PGD on an individual basis to a whole new level - Theoretically, it might be possible to eradicate many debilitating genetic conditions from certain family lineages or even from society as a whole by selecting for children who do not possess any disease causing alleles. For diseases transmitted by recessive alleles of a gene, it would a relatively simple task to selecting an embryo which possesses only the dominant alleles, and thereby eliminate not only the chances of that child having the disease but also the chance of that child being a "carrier" and passing the disease on to his or her offspring. To take this one step further - what if we could eliminate these well-understood genetic diseases from the human population entirely? Unfortunately this is probably impossible, as it would mean that every couple having a child would need to undergo IVF treatment, and the number of couples who use IVF is minuscule in comparison to that of natural methods. But, it is an interesting thought that selection for disease-causing genes in this way could completely eradicate a diesase in a similar phenomenon to the elimination of the smallpox virus from society through widespread vaccination.
The question of whether “PGD should be implemented for couples who choose IVF through necessity”, however, is definitely debatable. On the one hand, surely it is the parents’ right to have control over their IVF treatment, and if they believe that selection techniques such as PGD are morally wrong, then they should have the option of whether to choose PGD or not. On the other hand, surely it is better not only for that particular child, as well as society as a whole, to eliminate debilitating diseases simply by selecting an embryo without the dangerous genes? It is not as though the embryos are being altered in any “unnatural” way – rather we are screening pre-existing embryos with natural, random combinations of their parents' genes. In a way it is as if we are implementing our own 'forced' version natural selection, and while some probably argue that natural selection should not be tampered with and should simply be allowed to run its own course, if we have the knowledge and technology to prevent suffering, surely we are morally obligated to use it?
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