Against the Gene Genies.('Enough: Staying Human in an Engineered Age')(Book Review)

Enough: Staying Human in an Engineered Age, by Bill McKibben (Times, 288 pp., $25)

Woody Allen once said: "Today we are at a crossroads. One road leads to hopelessness and despair; the other, to total extinction. Let us pray we choose wisely." A diagnosis only slightly less depressing may be found in Bill McKibben's new book, Enough. Asking whether human technology has finally gone too far, this environmentalist-journalist answers: yes. Man's power to control nature is fast becoming the power to exceed all human limits, imperiling the very existence of our species. We have reached the technological "enough point." Restricting freedom is now the only way to save the planet.

So far, this is conventional leftism-no surprise coming from the author of such works as The End of Nature and Hope, Human and Wild: True Stories of Living Lightly on the Earth. But what makes this book interesting is that the main source of its angst is not global warming or ozone depletion, nor even that more recent bogey, genetically modified foods, but rather the genetic engineering of human beings- designer children-which until now has been a concern mostly of social conservatives.

As with the issue of human cloning, so now with genetic engineering: Some on both left and right are finding they have more in common with old adversaries than with traditional allies. If this keeps up, we might see the emergence of a permanent coalition, one that might be called "bioconservative": an alliance of those less-libertarian elements within the old coalitions that would forbid eugenics in order to preserve human dignity.

As McKibben notes, the idea of designer children no longer belongs purely to the realm of science fiction. In vitro fertilization is now being used to initiate nearly 1 percent of all American births, and an amazing 5 percent of births in parts of western Europe. Headlines daily announce the discovery of the "gene for" trait X or disease Y. Genetic testing and selection of embryos is becoming a routine service in IVF clinics, for fertile as well as infertile people. And some scientists are hoping even to create "artificial chromosomes" that might one day be inserted safely into early embryos at will.

Some would-be parents have come to regard reproduction as a bit like consumption, using preimplantation genetic diagnosis to ensure "a disease-free legacy," to have a child of the preferred sex, or even to create a tissue donor for a sick family member. It's not hard to imagine standard "options" evolving to include height, eye color, and the like. A few countries have responded to these developments with restrictive laws, but U.S. policymakers still tread lightly, for fear of seeming insensitive to infertile couples and carriers of disease genes.

Not so squeamish, McKibben roundly condemns child-design as a step too far. One hears echoes of Leon Kass and Francis Fukuyama (and, more remotely, C. S. Lewis) in his discernment of a straight line running from today's "disease-free legacies" to tomorrow's world of sub- and super-humans, and beyond that, perhaps, to multiple post-human species. If, as he fears, we face a Woody's choice between a post-human future and one that leaves such ailments as Down syndrome and even cystic fibrosis floating around in the gene pool-a choice between dehumanization and disease-he chooses disease. To the libertarians who would leave parents in the driver's seat, he retorts: "People shouldn't be ...