This book is an updated PhD thesis on the practical, technical and especially ethical aspects of pre-implantation genetic diagnosis (PGD). It presents the historical and philosophical development of Bioethics and its application to PGD and includes detailed discussion of the practical problems such as genetic counselling and informed consent, and a description of the techniques required for successful PGD. Also included is a questionnaire investigating the change in attitudes of Assisted Reproduction Techniques (ART) laboratories in Portugal between 2001 and 2010 concerning PGD, with particular emphasis on the law on ART introduced in 2006. The results of the questionnaire served as a basis for further considerations on the bioethical implications of PGD. This book is a substantial document suitable for specialists and non-specialists who are interested in the promotion of good practice in Human and Medical Genetics, the ethical aspects of PGD and comments on the genetic challenges that await future generations.