In 1988, Joseph Fletcher, one of the most influential American philosophers of the last half of the twentieth century, predicted the coming of a "biological revolution" that will be no minor alteration in the way things are, no mere reform. The Harvard University professor and "patriarch of bioethics" predicted that biotechnology will lead to a transformation of culture "of such a radical nature" that life scientists will one day become more powerful agents of social change than "Presidents and Parliaments and Pentagons."

How will such awesome power be exercised? Using the tool of genetic screening, biotechnologists will exert "quality control" over our progeny, a process that Fletcher hoped will permit society to weed out disabled people and those he deemed inferior. "There is no such thing as a right to bring crippled children into the world," Fletcher bluntly declared barely forty years after a shocked world learned that German doctors had euthanized tens of thousands of disabled infants during World War II. "If we choose family size, we should also choose family health.... If the State is morally justified in repelling an unwelcome invader ... why shouldn't the family be protected from an idiot or terribly diseased sibling?"

Joseph Fletcher believed that humans have an obligation to become, quite literally, self designing.

The state's right to excise an imperfect child, as if it were no more than a tumor, was only the beginning of the radical policies that Fletcher yearned to see implemented. He was eager for bioscientists to master the skills required to create "superior people" through applied genetic enhancement, and he believed that humans have an obligation to become, quite literally, self designing; or in the Latinism he devised, Homo auto fabricus.

Much of Fletcher's advocacy could have been taken right from the pages of Brave New World, but with one crucial difference: the genetic manipulations that Huxley so urgently warned against, Fletcher wholeheartedly embraced. Not only did he extol a radical eugenics philosophy in which biotechnologists would be permitted to shuffle human genes like a deck of playing cards, but he advocated the manufacture of a slave caste of "man-animal hybrids," the moral equivalent of Huxley's fictional Epsilons:

 "Chimeras [part human/part animal] or parahumans might legitimately be fashioned to do dangerous or demeaning jobs. As it is now, low-grade work is shoved off on moronic and retarded individuals, the victims of uncontrolled reproduction. Should we not program such workers 'thoughtfully' instead of accidentally, by means of hybridization?"'

Of course, not all of Fletcher's hopes for biotechnology were so blatantly immoral; indeed, in his last book, The Ethics of Genetic Control, he conceded that biotechnology's staggering power could harness great good or unleash profound evil, or do both at the same time. Thus, even as Fletcher was promoting discriminatory Brave New World values, he was concomitantly urging that biotech be put to unquestionably beneficent uses that would not alter human nature or demean human dignity. For example, he hoped animals could be genetically modified so that their organs could be procured for use in transplants—xenotransplantation—to "relieve human beings of the risks or inconveniences of the donors' role." Today, such experiments are well under way. Researchers have created herds of cloned, genetically modified pigs, which they hope will one day end the chronic shortage of transplantable organs. Should this biotechnology pan out and should we find ways to ensure that animal illnesses will not be passed to human populations, the potential for xenotransplantation to alleviate human suffering is hard to overstate.

“If the State is morally justified in repelling an unwelcome invader ... why shouldn’t the family be protected from an idiot or terribly diseased sibling?”

I cite Fletcher's enthusiasm for genetic engineering because he became one of our most influential thinkers by eloquently advocating "unthinkable" ideas, and because his ideas once seemed wildly futuristic. But now, less than two decades after he propounded "the ethics of genetic control," scientists have developed many of the tools necessary to bring to fruition both the light and the dark sides of Fletcher's prescient vision.

If the cost of biotechnology's alleviation of human suffering is our acceptance of the Brave New World miasma, we will not get there in one giant leap. Rather, we will descend into the darkness in small steps, all but unaware that the shadows are lengthening. We may already have taken the first step on the proverbial thousand-mile journey. By now many of us readily accept the principle that human embryonic life, toward the end of developing new medical cures, can be sown, reaped, harvested, patented and sold—just like any other natural resource or product.

But this is only the beginning of biotech's policy agenda. In step with the widespread acceptance of embryonic stem cell research, advocates began insisting that biotech should also be permitted to engage in human cloning for biomedical research (CBR), justifying these experiments on the same grounds as they had stem cell research using IVF embryos. But cloning goes far beyond ESC research: it explicitly creates human life for the purpose of experimenting upon and destroying it. Moreover, the information gleaned in such experiments would have the perhaps unintended consequence of hastening the day of cloned human babies. Should that threshold ever be crossed, the campaign to permit genetic engineering of progeny—the fabrication of "designer babies" would soon kick into high gear.

At this point, those who disagree with my viewpoint will probably criticize me for summoning the "slippery slope" line of argumentation, which goes something like this: If we permit controversial activity A, it will set in motion forces and changes in attitude that will lead inevitably to the even more controversial activity B. And then, before you know it, we'll be in free fall all the way down through the alphabet to activity Z.

Some believe that slippery slope arguments are exercises in alarmism. However, when it comes to the controversies dealt with in these pages, the philosopher and social critic Richard John Neuhaus has it right; asked whether he believed in the slippery slope, he replied, "Yes, like I believe in the Hudson River."

Human embryonic life can be sown, reaped, harvested, patented and sold, just like any other natural resource or product.

The history of in vitro fertilization (IVF) illustrates how easily biotech can go slip-sliding away. IVF is a fertility treatment in which a woman desiring to become pregnant is hyperovulated—i.e., given an injection of hormones resulting in her releasing 7-10 mature egg cells during her monthly cycle, instead of the usual one egg cell. These are then extracted with a needle and mixed with the prospective father's sperm in a Petri dish. If successful, the procedure results in fertilization and the development of one or more embryos.

The embryos are nurtured in the laboratory for nearly a week, and then several of them are inserted into the woman's uterus at the appropriate time in her menstrual cycle. If implantation occurs—many embryos don't implant—the woman becomes pregnant. If all goes well thereafter, she experiences a normal pregnancy and birth. More than one million children worldwide have been born as a result of IVF since the first socalled "test tube baby," Louise Brown, entered the world in 1978.

IVF was morally controversial when it was first developed. In addition to potential health concerns, some worried that society would be impotent to place reasonable limits on IVF, and that the technology would lead to an inevitable coarsening of our views about the inherent worth of the individual and society's respect for nascent human life.

Others dismissed these worries as overwrought. One notable critic of the critics was Ellen Goodman, a nationally syndicated newspaper columnist. In 1980, she wrote in support of permitting the first IVF clinic to open in the United States:

"A fear of many protesting the opening of this clinic is that doctors there will fertilize a myriad eggs and discard the "extras" and the abnormal, as if they were no more meaningful than a dish of caviar. But this fear seems largely unwarranted."

Her point, one with which I agreed, was that IVF could be a great boon to couples experiencing fertility difficulties, without leading inevitably to our becoming indifferent to the intrinsic worth of nascent human life. Unfortunately, that's not how things turned out.

Fletcher advocated the manufacture of a slave caste of “man-animal hybrids.”

To avoid subjecting women to the repeated rigors of hyperovulation, doctors do indeed now "fertilize a myriad eggs" and deep-freeze the extras for possible future use. Since not all embryos that are introduced into the uterus successfully implant, far more embryos are created than are actually used. As a result, hundreds of thousands of frozen embryos are maintained in cold storage, and IVF embryos are routinely dealt with in ways that were once seen as beyond the pale. Today, we do discard the "extras" and the abnormal, and we don't give much thought to the implications of our acts. Once the procedure became fairly routine, the very things that Goodman assured us would not occur quickly became commonplace and uncontroversial. And a new line has been crossed as nascent humans are now looked upon as "products" for use in ESC research.

A common defense against the slippery slope argument is for proponents to assert that they are aware of the dangers, but that our moral sense, backed by reasonable regulations, will protect against abuses. Thus, Goodman's 1980 column concluded:

I think we should neither fund such a [IVF] clinic at this time, nor prohibit it. We should rather monitor it, debate it, and control it. We have put researchers on notice that we no longer accept every breakthrough and every advance as an unqualified good. Now we have to watch the development of this technology, willing to see it grow in the right direction and ready to say no.

"No" isn't a word that many biotech researchers accepted then, and even fewer accept it now In any case, Goodman may have been only paying lip service to the idea of monitoring and controlling this innovation; those who have labored to pry open the barn door often shrug their shoulders later on if they learn that the horse has escaped. So when I first came upon Goodman's old column, I e-mailed her, inquiring why, despite her earlier reticence and her clear statement that society should not support "every breakthrough and every advance," she has repeatedly declined over the years to actually say No as the bandwagon goes careening downhill. She courteously responded, telling me that since the date of the above-quoted article, "My lines have changed"—by which I take her to mean that she has evolved in her thinking to the point where she now readily accepts courses of action she would formerly have considered anathema.

The ease with which ethical lines around IVF were redrawn should serve as a reminder of how readily we moderns accept an almost “anything goes” approach to technology.

And that's precisely how the "slippery slope" works. Despite assurances that there are limits beyond which we surely will not go, those supposedly solid walls disappear like mirages as we approach them. Assisted reproduction continues to be essentially unregulated in the United States, and now many, including Goodman, urge that we cross to a completely different moral environment in which IVF embryos aren't necessarily regarded as possible future babies, but as mere harvestable commodities. Surely, this is a dehumanizing view that would have been unthinkable to Goodman and many another supporter of IVF when the technology was first developed.

Does this mean that we should have outlawed IVF, then or now? No. But the ease with which ethical lines around IVF were redrawn should serve as a reminder of how readily we moderns accept an almost "anything goes" approach to technology. More to the point, if an innovation as benign as a medical treatment to help infertile couples has led us to the Rubicon where we have come to look upon "spare" IVF embryos as mere bundles of cells rather than as potential people, what might happen to our morality when scientists wield the godlike power to refashion our biological nature?