Genetics and biotechnology promise a future of unprecedented health and longevity: DNA screening could prevent many diseases, gene therapy could cure them and, thanks to lab-grown organs, the human body could be repaired as easily as a car, with spare parts readily available. Ultimately, the aging process itself could be slowed down or even halted. But what impact will this have on who we are and how we will live? And, with our mastery of the genome, will the human race end up in a world divided by genetic apartheid?

• Michio Kaku