To breed a better human - we have the technology

Gene ExpressionBy Razib KhanDec 6, 2006 3:54 PM


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A few years ago the developmental geneticist Armand Leroi burst on to the scene with the engaging book, Mutants, and a controversial op-ed where he attempted to rehabilitate the concept of race. Leroi's op-ed spawned a rebuttal website which brought together a variety of scholars from disparate disciplines to refute his arguments. Never one to shy away from controversy Armand has published a new essay, The future of neo-eugenics, where he lays out what is happening, and will possibly happen, from the perspective of an evolutionary biologist. The great thing about Armand's work is that he cranks out the numbers. I found that some of my earlier assumptions in regards to eugenics were fallacious. So, here are the numbers....

  • Each year 4 million babies are born within the United States. The expectation of Down Syndrome based upon the rate of chromosomal mutation would be 6,150 babies. Leroi estimates that only 4,370 babies with this condition are born each year, extrapolating from an abortion rate of 29% of fetuses diagnosed with Down Syndrome in Atlanta, GA, and Hawaii (the only places where there are data).

  • In Western Australia 32% of the fetuses with Down Syndrome were aborted, in South Australia 75%, in Taiwan 80% and in Paris 85%.

  • Please remember though that Down Syndrome males are sterile, and females far less fertile than the median, so the eugenical effect of this is only epiphenomenal.

  • Leroi also points out that increased frequency of conception by older mothers has balanced out the eugenical impact of abortions so that the number of individuals with this condition has been constant (i.e., the abortions cut into a larger number of potential Down Syndrome children).

  • "40% of infants with any one of 11 main congenital disorders were aborted in Europe."

  • "... in 2002, 20% of fetuses with apparent birth defects were aborted in G8 countries--that is, between 30,000 and 40,000 fetuses."

  • "In Western Australia, neonatal mortality rates due to congenital deformities declined from 4.36 to 2.75 per 1,000 births in the period from 1980 to 1998. Half of that decline is thought to be due to the increase in abortions of abnormal fetuses...."

  • In Taiwan, screens for thalassaemia mutations have caused the live-birth prevalence of this disease to drop from 5.6 to 1.21 per 100,000 births over eight years

  • "...comparative genomic hybridization (CGH) microarrays could be used to screen a single embryo or fetus for thousands of mutations."

  • Based on the number of known mutations Armand calculates that it should be possible to predict disease to a reasonable confidence in 1 in 252 embryos.

A major caution about massive genetic preimplantation screens is that they would be preimplantation. That is, some sort of IVF would be needed. It seems implausible that this would be widespread, but Leroi points out that IVF procedures already make up several percent of the pregnancies in Western nations. The cost of a typical IVF procedure is that of a medium sized car, and crucially, the cost of many diseases over one's lifetime is far greater (IVF would be like "insurance"). Lero concludes thus:

Some readers might find it peculiar that in this discussion of neoeugenics, I have not considered the ethical or legal implications with which this subject is generally considered to be fraught. Although I do not doubt their importance, I simply have no particular knowledge of them.

One might find this sort of conclusion glib, but before one can make ethical judgements one must understand of what one speaks, and that is the crucial role of public intellectuals like Leroi. As I've noted, concepts like genetic load, mutational load and the importance of reproductive variance in selection are common concepts which evolutionary biologists are aware of, and over beers many an objective scientist will mull over the implications of higher fertility of lower socioeconomic orders, the problems that might occcur because of the survival and reproduction of those whose fitness is instrinsically burdened with illness palliated by medical intervention and the long term evolutionary arc of our species. Armand's piece points out several important issues.

First, the new eugenics is already here.

Second, the new eugenics will become more powerful as information gathering via genomics becomes more omniscient, and medical interventions in fertility become more omnipotent.

Third, there is variance in the extent that different individuals and groups are willing to avail themselves of the opportunities offered by the new eugenics

. A acquaintance of mine who has been involved in research in France offered that higher socioeconomic status parents were much more likely to abort than lower socioeconomic parents when the fetus exhibited abnormalities. Germany tends to frown upon eugenical technology (for obvious reasons), but most East Asian nations have few compunctions about utilizing these tools in family planning. For evolution to occur via natural selection all you need is differential reproduction tracking traits which exhibit heritable variation, the new eugenics will do nothing but accelerate and modulate this trend. A new story in The New York Times, Wanting Babies Like Themselves, Some Parents Choose Genetic Defects, illustrates these issues on a less abstract level. You have here parents who want "children like them." Deaf lesbians who seek out a sperm donor who is deaf so that their child can be deaf, and consciously deny their son technology which could palliate his lack of hearing. The reason? Because he would not be fully part of the deaf community. Additionally a difference between parent and child like the ability to hear would introduce a chasm. The other primary group highlighted are individuals with darwfism. One mother-to-be states:

Mary Ellen Little, a New Jersey nurse with dwarfism, had her first daughter before a prenatal test for achondroplasia was available. For her second child, she had amniocentesis. "I prayed for a little one," meaning a dwarf, she told me. The wait, she recalled, was grueling, since "I figured I couldn't be blessed twice, but I was." Both her daughters, now 11 and 7, are "little people.

Is this ethical? I don't know, that's up to your values. Some people might say that it is hard to grow up in the world as a dwarf, and that dwarf parents are doing wrong in seeking to create children who perpetuate this abnormal condition. But people could also say the same for being born of a minority racial type. Should non-whites simply not reproduce so they do not perpetuate suffering in the next generation? This is a philosophical position taken by some religious groups in the past as an argument for celibacy, so it isn't a novel idea. There is the concern by the dwarf parents that a "normal" height child won't relate, that the difference would induce a strain. The deaf parents who seek a deaf child often give the same rationale, that they want children who are like them. And yet what about parents who are of different races, should they not have children because the child won't look like either of them, and would be "out of place" no matter where they were? Perhaps ugly people shouldn't reproduce, we know how the ugly are teased. And so on. These questions don't have easy answers if you are a mere mortal. For myself, I am much more concerned about children born deaf than children born dwarves. The latter are in a difficult position, but they are not invisible and they can communicate easily with the rest of our species. In contrast, deaf children are boxed in by the nature of their lack of a hearing facility. What if blind parents wanted to genetically engineer a blind child who they could relate to? What are children, are they ends toward parental satisfaction and fulfillment? Or are children something that we as a community all have a stake in? An important consideration is that health care is partly a public good, and if society is expected to pay for particular medical bills one might assume that society should have a say in which children come into the world. Ultimately I think the choices should be individual, but when they become ubiquitous I think we will need to demarcate Good and Evil, optional and mandatory. We're just starting.... Update:Download Leroi paper .

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