There'll Never Be Another You
By Ronald Bailey
(Copyright (c) 2001, Dow Jones & Company, Inc.)
Renegade fertility specialists Severino Antinori and Panayiotis Zavos, along with Brigitte Boisselier, a scientist for the crackpot "Raelian" cult, claimed in front of God and the National Academy of Sciences this week that they plan to begin cloning babies this year. And now the whole world is up in arms, not least the U.S. House of Representatives, which just passed legislation outlawing both therapeutic and reproductive human cloning .
Will there be human clones among us soon? Actually, to be pedantic, there are already plenty of human clones -- and these are identical twins, possessed of exactly the same genes. Considering these natural clones helps us to think clearly about what clones produced in vitro would be like. No one doubts that twins are clearly different people with distinct points of view. Their existence points up the fact that individuality does not reside in our genes, but in our brains and bodies.
A baby born through cloning would simply be a younger twin and would not be the "same" person as the one who donated genes. Some people oppose human cloning because they worry that a clone's life would be "less open" than than that of people produced in the conventional way. Clones would be born with expectations, goes the argument, because people with that exact set of genes would have preceded them. The novel genomes produced through sexual reproduction, it is said, somehow confer more "openness" to the lives of their carriers.
This view is genetic essentialism. Studies of twins find generally a 60% correlation in characteristics such as intelligence and temperament. Clones, who will be twins displaced in time, and who will therefore have very different life experiences, will likely share even fewer similarities with their genetic forebears than identical twins do today. Anyone seeking to make exact duplicates of themselves or other loved ones through cloning is going to be very surprised.
Once the public understands the limitations of reproductive cloning -- for example, one can't bring back the dead or create a newer, younger versions of oneself -- human cloning will likely be used mostly by infertile couples who have no other way to bear biologically related children. For the rest of us, producing children the old-fashioned way will remain a lot more fun, and a lot cheaper.
A moral objection often heard is that cloned children would be not ends in themselves but means for parents' self-aggrandizement. And sadly this may be true for some cloned children, but it is also true for many children born in the conventional way. Yet, the considerable emotional and financial investment that the parents of cloned children will be making indicates that they will be cherished for themselves, not treated as mere objects.
So what about the renegade cloning projects presented at the National Academy of Sciences meeting? As expert after expert testified, the chief problem in cloning mammals so far has been its inefficiency -- it takes a lot of failed embryos to produce one healthy cloned animal. Right now, only 2% to 4% of mammalian clones are long-term survivors, and even most of them are not healthy.
Why is there such a low survival rate? In a nutshell, the problem with mammalian cloning may be that the genes from the nuclei of mature cells may have lost their proper imprinting. So when these mature nuclei are inserted into enucleated eggs to produce embryos, their imprinting is wrong. Since there is currently no way to restore it, either paternal or maternal genes affecting fetal growth may end up being dominant, creating the severe developmental imbalances seen in cloned animals.
Although Drs. Antinori and Boisselier claimed that they plan to test clones for abnormalities, there is no test now available to check whether genes are properly imprinted or not, so bringing a healthy clone to term is largely a matter of chance -- and a slim chance at that.
Instead of trying to create human babies through cloning now, it would be far better for research to continue on cloning other species until scientists understand why the abnormalities occur and can reliably correct them. For example, it might be possible one day to test a whole suite of pre-embryos and then implant only the ones with the proper imprinting. A good benchmark for deciding to proceed with human reproductive cloning would be when researchers are reasonably sure that clones would suffer no more likelihood of birth defects (about 2%) than do children produced by sexual reproduction. It's too early now.
The would-be cloners counter that attempts at human reproductive cloning are little different from the first efforts at in vitro fertilization in which researchers implanted scores of embryos before the first one worked, bringing Louise Joy Brown, the first "test tube" baby, into the world in 1978. They are wrong. In the case of in vitro fertilization, animal research had identified no problems with increased birth defects resulting from the procedure. That's clearly not the case with mammalian cloning right now.
Attempting to clone a human baby now can be thought of as behaving so negligently that one has a high likelihood of maiming a person. It is appropriate to protect people from very negligent, or reckless, behavior. So, should the federal government outlaw attempts at human reproductive cloning? Far better would be a moratorium similar to the one adopted by researchers in the 1970s, when gene-splicing first began. That moratorium was lifted a couple of years later when it became clear that genetic engineering posed no great safety problems. If Drs. Antinori, Boisselier and others persist in trying to produce cloned babies, Congress might consider a ban limited to five years during which research on cloning other mammals proceeds.
Of course, the House of Representatives just passed legislation that would criminalize therapeutic as well as reproductive cloning . In therapeutic cloning , researchers hope one day to produce stem cells by taking the nucleus from a patient's own cells, install it in an enucleated egg and then start it dividing as an embryo in a petri dish. After a week or so, stem cells would be harvested and, if all goes well, transformed into treatments like immunologically compatible heart cells or nerve cells to repair a patient's damaged organs. They would be perfect transplants.
It has been reasonably estimated that tens of millions of Americans suffering from diabetes, Parkinson's, and heart disease might benefit from this technology. Further down the road, therapeutic cloning research could lead to ways to create stem cells without recourse to human eggs.
Opponents of this research claim to worry that embryos cloned for therapeutic purposes might be diverted and used to clone babies. It may well be true that therapeutic cloning research might make reproductive cloning easier to do, but should therapies or technologies be banned because they could be abused? If potential for abuse were the threshold, Congress would be very busy banning such things as automobiles, pain medicines, whiskey and tattoos.
The Senate will have a chance to consider this issue when it returns from vacation and senators must not allow themselves to be stampeded by the foolish claims of a few quacks into criminalizing the potentially very beneficial research on therapeutic cloning .
In the meantime, for the sake of infertile couples who look to reproductive cloning as a way of having kids one day, and for the sake of those kids themselves, a moratorium on human reproductive cloning should be instituted, enforced either by professional sanctions, or by law if necessary.
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Mr. Bailey is the science correspondent for Reason magazine.