Mar 03 2009
About a year and a half ago I wrote a post about techniques to select the sex of your child. The gist is this – it is possible to select with almost 100% accuracy the sex of your child if you are conceiving through IVF (in-vitro fertilization). However, there are no home-kits or other techniques on the market that work. There are sperm-sorting technologies (the sex of a child is determined by the sperm from the dad, not the egg from the mom) being developed and in clinical trials, but nothing yet on the market that I have seen.
At the time I speculated that such technology is likely to progress to disease prevention and then to selecting desirable traits not directly related to health. And then further to genetic engineering.
Well, an IVF clinic in the US has made a significant step in that direction, and the predictable controversy has ensued. The Fertility Institutes are now offering their clients the ability to select certain traits, like hair and eye color, of the eggs they implant.
IVF and PGD
In-vitro fertilization is the technique of extracting eggs from a female donor (either the proseptive mother or a separate donor), fertilizing the egg with sperm from the dad (or again from a donor) and then implanting several fertilized eggs into the mother or a surrogate. The success rate varies based upon many variables – age of the mother, whether or not the embryos were cryopreserved or used fresh, and the experience of the clinic. But generally rates of live births from IVF are around 30-40%. Per embryo the number is lower, which is why several embryos are transplanted at once, creating the possibility of multiple births.
PGD stands for preimplantion genetic diagnosis – genetically analysing embros prior to implantation. The primary purpose of this is to increase the success rate of IVF. Originally embryos were visually inspected under the microscope and the healthiest looking embryos are implanted. This is still the standard in many clinics. However, some clinics offer PGD, which takes a look at the chromosomes in each embryo.
Human cells, including the cells in embryos, have 23 pairs of chromosomes, including the XY sex chromosome. Chromosomal analysis is able to detect aneuploidy, which is an abnormality in the number of chromosome pairs. For example, there may be one or three of one type of chromosome. Chromosomal analysis is also able to detect with near 100% accuracy the sex of the embryo.
By selecting out embryos with normal chromosomes the success rate of IVF is increased significantly, even allowing for the implantation of fewer embryos. This much is not controversial and represents a technological advance for IVF.
IVF clinics have also been offering more sophisticated genetic analysis. What they do is take a very precise biopsy of each embryo. They wait 2-3 days post fertilization when the embryo still have only a few cells and the cells are still distinct enough that one can be removed without disturbing the others. Also, at this stage each cell in the embryo is still undifferentiated, so removal one cell has no effect, the others can still go on to produce a normal child. In fact, this is the stage at which identical twins are formed – the embryo splits in two and each half is capable of developing into a normal child.
The single cell removed from the embryo can now be analyzed not only with chromosomal analysis but genetic analysis for single gene mutations. They currently screen for over 90 specific mutations, from muscular dystrophy to sickle-cell anemia. Again – this is not controversial. If someone is going to go through the painstaking process of IVF, they might as well choose embryos that do not have the genes for a horrible disease.
But now is where the controversy comes in. This same company is offering as part of their genetic analysis the option of choosing cosmetic details, like eye and hair color. Because these traits can be genetically complex, they do not make 100% guarantees for these traits.
The controversy seems to be based entirely on subjective moral sense. At least I have not heard any cogent arguments as to why parents should not be free to make such choices with their own sperm and eggs.
In a BBC article on the topic Dr. Gillian Lockwood, a UK fertility expert and member of the Royal College of Obstetricians and Gynaecologists’ ethics committee, is quoted as saying:
“If it gets to the point where we can decide which gene or combination of genes are responsible for blue eyes or blonde hair, what are you going to do with all those other embryos that turn out like me to be ginger with green eyes?”
She warned against “turning babies into commodities that you buy off the shelf.”
This sounds like an emotional appeal. I’m not sure what the moral principle she thinks is at work here. Is it just fooling with nature, or that genetics should be random? This sounds like the same kind of arguments that cropped up when the girl had the baboon heart transplant. People protested that animal proteins should not be mixed with human proteins. Why? I guess all those people with pig or cow heart valves should not have had their life-saving surgeries.
I think that part of the moral squeamishness comes from the tendency for people to self-identify with their physical characteristics. Dr. Lockwood seems to identify with being a ginger, for example. But as cosmetic technology advances the ability to change our physical look is progressing rapidly. It is likely that future generations will change their physical characteristics as casually as we change out clothes.
One potentially legitimate argument is more of a practical than moral one. If too many couples select the sex of their child we may end up with a surplus of one gender over the other. However, at the moment IVF is such a small fraction of births that this is not a concern. If gender selection becomes more prominent in the future then it would be reasonable to monitor the effect of choice on male/female ratios, but until then the argument is premature.
Incidentally, the UK currently bans gender selection with IVF. Only medical screening is allowed.
Another controversial point comes from the right-to-life camp who feel that it is immoral to create extra embryos. In Italy, for example, the production of extra embryos itself is illegal, and this, of course, eliminates all gender, medical, and cosmetic selection. I understand that this is a personal moral choice and not one that can be objectively resolved.
Personally I have no problem with parents using technology to choose which of their genes they pass onto their children, rather than being forced to accept what chance provides. I file this under personal choice. I do not see a compelling interest by the state to illegalize this choice. At least the burden should be on them to prove a potential risk to public or individual health or some compelling state interest before infringing upon individual rights.
Also I see this technology as inevitable. Moral arguments based largely on being uncomfortable with new technology tend to fade over time. Genetic selection to avoid disease is already here and there is no serious opposition to it. Next is line is health promotion (better genes for heart health, or reduce the risk of diabetes). The financial benefits of reducing chronic illness alone are likely to overwhelm any moral compunctions.
Future generations who take genetic selection for health for granted will not likely have much of a problem with selecting other progressively superficial traits. There are plenty of people today who are comfortable with it.
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