Gene Expression blogger Razib has written some thoughts on evolutionary biologist Armand Leroi's expectations for the future of eugenics (labelled neo-eugenics to try to distance it from eugenics advocacy of previous eras)
To greatly reduce the rate of mutations in births requires widespread screening and a willingness to abort based on the results. Or genetically screen IVF embryos before implantation. In the longer run we will gain the ability to do gene therapy to repair genetic defects in embryos. But due to the risks involved and likely regulatory resistance I expect that's decades away from routine procedure.
If all embryos were screened and if women halted all pregnancies which have genetic defects the percentage of births with genetic diseases avoided would be pretty low.
Notice the emphasis on known. Of course many more unknown purely harmful mutations will be found in the coming years. So the incentive to screen to avoid harmful mutations will rise.
Also, we will come across many more mutations that provide benefits under some conditions (e.g the sickle cell anemia mutation which confers malaria resistance) but at painful costs. Expect quite divisive controversies on which genetic variations are harms and which are benefits.
Some argue against all attempts to prevent the birth of babies with genetic diseases. Others argue against specific methods (e.g. abortion) to avoid such births. Still others argue that abortion or pre-implantation genetic diagnosis (PGD - used before implantation of embryos created with in vitro fertilization) are acceptable only to avoid true genetic defects.
The argument for restricting the use of, say, PGD only to avoid genetic defects immediately runs up against the question of what is a genetic defect and what is a genetic disease. The genetic variation for sickle cell anemia was selected for because it conferred resistance to malaria. It was not a defect for those who it helped to survive malaria infection.
I predict we will find many genetic variations that confer some benefit at some cost. Sometimes the benefit will be irrelevant under modern conditions (e.g. sickle cell anemia for someone living in temperate climes or with benefit of drugs). But that won't always be the case. Real thorny ones will involve trade-offs that come from genetic variations that provide both high costs and high benefits.
For example, imagine a genetic variation that boosts IQ at the cost of greater chances of feeling depressed if one encounters tough times. Or imagine a genetic variation that allows one to live longer but at the cost of making one more lethargic. People will argue to select for or against all manner of genetic variations.
Cost and benefit calculations will depend in part on one's values. But one's expectations of future technological advances will also figure into the question of what is a cost and what is a benefit. Suppose some genetic variation increases a woman's chance of breast cancer in her thirties but also will raise her intelligence. That might well be the case for the BRCA gene variations that contribute to cancer risk. A person might plausibly argue against selecting out such variations on the theory that 30 or 40 years from now cancer will become easily curable.
To screen most effectively requires use of in vitro fertilization (IVF).
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").
As the number of genetic variations one wishes to avoid rises so does the need for IVF and genetic screening on multiple embryos. But the greater the number of genetic variations to avoid or to selective for the greater the potential benefit.
As we learn the significance of large numbers of genetic variations the primary motivation for gene selection will be to get desired features rather than to avoid genetic diseases. The desire for higher intelligence will make IVF become the preferred way to create babies for one reason: People will embrace IVF to make smarter babies. They'll also embrace it to make better looking children. The prospect of better smarts and looks will cause prospective parents to embrace IVF and genetic screening with a passion.
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.
Smarter and higher economic class people will embrace eugenic technologies more rapidly and more enthusiastically. The smarties will select for smarter children with attributes that will make them more successful. Therefore I predict a widening of the gaps between the most and least successful segments of societies and of the gaps between societies.
Elites will promote subsidies and propaganda campaigns to encourage the cognitively less able and poorer people to also use eugenic reproductive technologies. But even when the dumber folks opt to use genetic screening they'll make less optimal choices for their offspring.
I would add a fourth point to the three points Razib enumerates: Those who will avail themselves of methods to select offspring genetic endowments will make different average decisions as members of different societies, races, religions, and other groupings. This will tend to cause a divergence of the human race into groups that will become more genetically dissimilar. Genetic variations that cause differences in methods of cognitive processing will have the greatest political impact as groups clash due to genetically caused differences in values and in understandings of the world.
|Share |||Randall Parker, 2006 December 17 08:00 PM Bioethics Reproduction|