What Can We Expect from Human Genetic Engineering?

Lee Silver, Remaking Eden: Cloning and Beyond in a Brave New World, Avon Books, 1997, 317 pp.

What can we expect from human genetic engineering? How will cloning change our species? Can governments misuse genetic technology? These are some of the questions Lee Silver tries to answer in Remaking Eden. This book is so breezy it reads as if it were pitched to readers of Mademoiselle, but Prof. Silver clearly knows his field and makes no secret of his enthusiasm for using science to improve on nature. Whatever scruples — religious or otherwise — one may have about the advisability of tinkering with human reproduction, this book leaves little doubt that human cloning and designer babies are likely to be common in the next century.

Just a Small Business

Prof. Silver explains that cloning will be a crucial step in our ability to manipulate reproduction. Last year’s successful cloning of a sheep means there should be no scientific obstacles to doing the same thing with humans, but what is a clone and how does cloning work? A clone is an exact genetic copy of an organism. Clones are easily produced by plants that can be propagated from cuttings, but animals don’t reproduce that way. A clone of a person would be made by putting his genetic material into an embryonic cell, implanting that cell in a womb, and letting it develop to term. Biologically, a clone is no different from an identical twin, except that it is born later — perhaps many years later.

The news of the sheep cloning was met with widespread hostility, and people from President Clinton on down urged that cloning of humans be prohibited. Prof. Silver thinks opposition is both futile (because cloning will be impossible to ban) and misplaced (because cloning will be good and useful). He argues that fancy reproductive genetics cannot be prevented because it does not require large-scale investment, and can be done virtually anywhere. If the United States bans it, Singapore or North Korea or the Cayman Islands will welcome the small businesses that will inevitably spring up to provide it.

According to Prof. Silver, cloning and its associated techniques are good, partly because only individuals, not governments, are likely to use them. There are several reasons for this. First, human cloning starts with a single cell that must be grown into an adult, so it takes 18 to 20 years. Champion athletes or obedient soldiers cannot be cranked out of a clone factory fully-grown, and Prof. Silver suspects that few governments have the patience to wait for clones to grow up. He also reports that in the foreseeable future the chances of creating an artificial womb are slim to none, since the chemical communications between mother and fetus are too complicated to reproduce. Cloning will therefore require human wombs, and large-scale government cloning would require a slave army of young women compelled to produce and rear government-issue babies. This is improbable even under the worst dictators.

Who, then, would clone and why? Since cloning will be labor-intensive, only the rich will be able to afford it. Some people — and not necessarily egomaniacs — will want the nearest thing yet to another chance at life: the opportunity to rear a genetic carbon copy of themselves.

Prof. Silver offers other more exotic possibilities: A couple could go infertile before it had all the children it wanted and could decide to clone the one(s) it already had rather than adopt. A lesbian could decide to clone herself and implant the embryo in her “partner”’s womb — both women would then be “biological” mothers of the resulting child. If the only child of a couple were killed in an accident the parents might decide to clone the child (from its remaining tissue) rather than start over. At a more gruesome level, a clone might be produced because it would be a perfectly compatible organ donor for someone who needed new parts. Some types of useful tissue are already present in the fetus, so the clone could be aborted and all its useful bits harvested.

Cloning makes for startling possibilities. A woman who particularly admired her parents could clone them, have them implanted in her own womb, and rear them. She would then be the birth mother of people who were, genetically, her own parents. Also, since human tissues can be stored indefinitely in the deep freeze, a long-dead ancestor’s genes could be thawed out and given another try. A child could grow up to learn that what he had always thought was his brother was — genetically — his great-grandfather.

Prof. Silver points out that it is possible to clone someone who has never been born. An aborted fetus has all the genetic material anyone needs for cloning. Spookier still is what could be done with the fact that male and female fetuses already contain eggs and the precursors of sperm. If these were harvested and used for in vitro fertilization, someone could be born of parents who were, themselves, never born. Prof. Silver does not necessarily endorse any of this — he is simply explaining what is now or soon will be possible. And to those who find these ideas repulsive, he points out that when in vitro fertilization was first achieved in 1978 it was denounced as “playing God.” It is now practiced without controversy in 40 different countries, and by the end of 1994 some 140,000 people had come into the world that way.

He also notes that surrogate mothers — women who rent out their wombs — continue to ply their trade, despite bad publicity. In 1986, Mary Beth Whitehead refused to turn over a contract baby she had agreed to carry for an infertile couple, and the saga of “Baby M” wore on for months. Since then, states have passed laws governing commercial surrogacy, some banning it outright. Others, like Arkansas, are receptive to reproductive contracts and will enforce them even if the surrogate mother does not want to hand over the baby. Prof. Silver reports that surrogates are now selected with such care that there are no more battles over possession. His point is that a procedure that once provoked an outcry is now quietly flourishing. He predicts that other reproductive techniques that now seem outlandish will also gain wide acceptance.

Whatever happens, this will be sport for the rich: In vitro fertilization costs anywhere from $50,000 to $200,000 and the total costs of hiring a stranger to carry your child run to about $50,000.

Improving on Nature

Even more troubling for some people is the prospect of human genetic improvement, but simple techniques of this sort are already being used. If parents use amniocentesis to test an unborn child for genetic diseases, they have the option of aborting the fetus rather than have a baby with a serious defect. This is crude, all-or-nothing selection but it is still a refusal to leave reproduction to chance. Embryo selection is similar but more complex. When infertile couples resort to in vitro fertilization, they usually fertilize several eggs at once to make sure at least one will be usable. If several embryos are left to develop they can be examined and the most promising chosen for implantation. Soon it will be possible to change the genetic contents of the embryo so as to eliminate hereditary diseases and even add desirable qualities.

Prof. Silver notes that cloning will be central to this process because at the pre-implantation stage that will make it possible to work with batches of embryos rather than just one. Biological procedures are never 100 percent reliable, so reproductive genetics needs the margin for error that comes with genetically identical copies. A technician who would never attempt an uncertain maneuver on a single, laboriously-harvested, fertilized, and partially-developed embryo could try it confidently on 100 identical embryos.

Needless to say, there is much controversy about all this. Some people would view the 99 failed-and-discarded embryos as 99 abortions. Likewise, there are doubts about the advisability of tinkering with genetic characteristics that could be passed on to succeeding generations. Indeed, some of the probable methods do seem strange. For example, it should soon be possible to modify the precursor cells that produce human sperm. Harmful characteristics could be eliminated and helpful ones added. These cells could then be implanted into the testes of a pig or mouse, which would produce improved human sperm, which could be harvested and used for in vitro fertilization.

Whatever techniques are used, Prof. Silver suggests that in 100 years or so, true designer babies will be possible. A couple could select their own most desirable traits and add nice features from other people and even other species. There is no theoretical obstacle to stitching into humans the genes that give dogs a keen sense of smell or even those that permit echolocation in bats or dolphins. Humans may some day be able to see radio waves and infrared light, or even perform photosynthesis.

Prof. Silver recognizes that the children of people who can afford these techniques will dominate society. Every parent with enough money could have beautiful, talented, genius children. Prof. Silver even recognizes that these improved humans could quickly become a distinct species, or even several distinct species, depending on the set of characteristics they selected. Is this eugenics? Indeed it is, says Prof. Silver, who argues that even if the Nazis gave it a bad name, it would be irresponsible not to take control of our genetic destiny now that we are able.

Fantastic as all of this may sound, Prof. Silver is probably at his most convincing when he argues that unless the United States or some other superpower launches a global effort to prevent anyone anywhere from perfecting and practicing these techniques, reproductive engineering will surely come to pass. Parents want the best for their children, and with or without their government’s permission they will find a way to get it. Although there will not be new, improved human super-species in our lifetime, Prof. Silver argues that there is no harm in getting used to the idea now.