Could a child have two genetic mothers? Will parents someday soon be able to choose not only the physical characteristics of their children-to-be, but their personalities and talents as well? Will genetic enhancement ultimately lead to a split in the human species?

In this brilliant, provocative, and necessary book, Lee M. Silver takes a cautiously optimistic look at the scientific advances that will allow us to engineer life in ways that were unimaginable just a few short years ago—indeed, in ways that go far beyond cloning. In clear, engaging, and accessible prose, Silver demystifies the science behind a myriad of thrilling and frightening new possibilities, in a book that is essential reading for anyone who wants to understand the hopes and dilemmas of the American family in the twenty-first century.