play. our species has evolved by what we call the darwinian principles of random selection for almost four billion years. for the first time ever and forever starting from now we're going to have the ability to alter our biology in increasingly significant ways. and it's going to happen in stages. all using technologies that already exist. so the first stage is going to be using ivf, embryo selection, and our knowledge of what -- to read the genomes of different people, to be able to select from among, say it's 15 embryos in average ivf, then we're very likely -- >> you choose the ones that maybe don't have certain diseases but also maybe have blue eyes and fair skin or something? >> i mean, whatever has a genetic foundation will be subject to choice. when you have 15, say 15 fertilized eggs as in ivf now, your options are limited.