A few passersby denounced the owners as Nazis. But most people entered the store ready to plunk down their credit cards to change the genetic inheritance of their families. Shoppers initially requested one trait they wanted changed, but once they got into it, their shopping lists grew. Since Gene Genies offered people not only human genes, but ones from animals and plants, one man surprised everyone by asking for the survivability of a cockroach.

The shop's owners, T. Kim-Trang Tran and Karl S. Mihail, were thrilled at the success of their endeavor, particularly since none of the services they were advertising were yet available. Despite their lab coats, they were not scientists, but artists striving to serve as our moral conscience. "We're generating the future now in our art and giving people the chance to make decisions before the services actually become available," said one of them. (Their exhibit now exists in virtual reality at www.genegenies.com.)

Now that scientists have drafted a sequence of about 3 billion base pairs that make up our genetic constitution, we all face a momentous task: Trying ...