[Prenatal and preimplantation genetic diagnosis: decision tree, new practices?].

Preimplantation genetic diagnosis (PGD) purpose is to assess the genetic status of 3 day-old embryos. PGD offers thus to couples "at-risk" of a genetic disorder an earlier option to prenatal diagnosis (PND). At the beginning, PGD's indications, patients and law were very closed to PND, but PGD specificities are gradually raising. Particularly, indications vary considerably in countries where the absence of law authorizes all the practices. Some of these applications are moreover raising serious ethical issues. Even in France, where this activity is particularly supervised, the recent modification to the law marks this evolution.