The three themes that make up the title of this book have for the last few years occupied the pages of newspapers and magazines, and been the focus of ethics debates not only by specialists, but also by a wider public interested in the consequences and problems that the advances in science imply for human beings. This is a book of essays founded on two fundamental pillars: biology and the socio-ethical perspective. Nearly all the essays look at questions of human biology from the perspective of bioethics, that is, the social and moral consequences of the problems examined, always with an attempt to retain a balance between conceptual rigour and accessibility of presentation.