What should we think of the frozen embryos which defy the laws of time and threaten to survive to their genitors? What should we think of children who have been conceived by spermatozoid or ovocytes donations, by the lending or renting of an uterus? Using the knowledge of their daily experience, Claude Humeau and Françoise Arnal help us to understand the new techniques of procreation and tell the way of the couples who have chosen to use these techniques.