The eugenics fascinates. The eugenics frightens. Moreover, the spectre of this ideology, connected to a past rich in history, returns in strength and arouses fears of drift as for the progress of the scientific knowledge and their applications mainly in the debate on preimplantation genetic diagnosis. While we are interested in its normative framing, a historic approach allows to guide the legislator to not repeat past errors and to understand better the stakes. An eugenic law has already existed in Canada in sterilisation of the persons mentally disabled. In the light of this law and its history, the author wonders about the lessons which we can apply to preimplantation genetic diagnosis, a genetic technology allowing to select a child created in vitro according to his genetic profile.