Bill McKibben
The brash young science of genetic engineering, like a newly licensed teenager behind the wheel, is driving civilization toward "the biggest break with human history that we can imagine," journalist Bill McKibben warned a rapt audience at UC Berkeley on Tuesday night.

American society seems to be asleep in the back seat as it careers into a world where our grandchildren could become the first genetically modified generation, said McKibben, author of the sobering book "Enough: Staying Human in an Engineered Age."

The power to create "designer children," in McKibben's view, is one genie that humanity should leave in the bottle.

Yet the advent of applied human gene manipulation is rapidly drawing closer, as researchers gain greater mastery over the human genome without a corresponding mastery over where, if anywhere, to draw the line.

Would many parents hesitate to adjust an unborn child's genes to prevent a genetic disability? Or prevent dwarfism? Improve resistance to cancer? How about enhancing IQ or musical ability, or the eternal human dream -- prolonging life?

Given the great disparities in wealth and access to...