"Prometheus was the Greek demigod who stole a spark of fire and was punished by Zeus for his presumption. To many people, the enterprise of biotechnology is a Promethean risk, another example of humanity's self-destructive aspirations to play God... Powerful though our species has become, it is a mark of hubris to believe that we can play God." -page 215
I thought it was interesting that the section on ethics ended with a reference to Greek mythology. Myths and storytelling have always been used to teach, warning audiences not to make the same mistakes that the characters in the story did. And by comparing genetic modification to Prometheus stealing fire, an act that was punished with being sentenced to have his liver torn out daily, Grace drives home the point that scientists need to be careful with what they use their discoveries to accomplish.
But I'd like to disagree with Grace. I don't think it's a sign of hubris at all, nor do I think scientists intend to play God. Hubris means great arrogance. But accomplishments made through biotechnology are hundreds of years in the making. It's taken scientists centuries to get to where we are now, a great deal of time and effort, trial and error. And using that knowledge to make better food or cure disease doesn't seem at all arrogant to me.
I'd also like to point out that Prometheus was not a demigod, but a Titan. According to Greek mythology, he was tasked with helping to create mankind, which is why he stole fire in the first place, as he felt responsible for helping them. A demigod is the offspring of a god and a mortal, and as mortals had not yet come into being, Prometheus couldn't possibly have been a demigod.