In the mid-1970s, the public of the Western world was astonished to learn that scientists had recently invented ways to move pieces of genetic material, the very blueprint of life, from one species to another. Boosters claimed that this new technology of moving and changing genes, which came to be called genetic engineering, would lead to more abundant food supplies, inexpensive medicines, and cures for currently untreatable diseases. Naysayers, on the other hand, feared that it would lead to unstoppable plagues of disease or other environmental disasters.

Supporters and opponents of genetic engineering were just as divided about the basic ethics or morality of the technology as they were about its practical implications. Supporters said it was nothing more than an extension of what breeders of plants and animals had been doing for thousands of years and, indeed, what nature itself did through evolution and natural selection...