Harris 1993 argues that even if gene-therapy for removing disability or for enhancing normal human traits is a form of eugenics, it is morally sound. He identifies the morally unsound aspect of eugenics with the idea that "those who are genetically weak should be discouraged from reproducing". He objects that eugenics properly understood maintains that "everyone should be discouraged from reproducing children who will be significantly harmed by their genetic constitution". Thus, eugenics through gene-therapy is morally sound because, unlike past eugenics, it might "enable individuals with genetic defects to be sure of having healthy rather than harmed children". Wikler 1999 provides a short history of eugenic movements and argues that we must learn from it, for instance by avoiding genetic determinism, class and race biases and the conviction that genetic improvement overrides the freedom of the individual whether and with whom to procreate. Wikler tries to identify the "original sin" in Eugenics, which leads him to analyze and discard many usual objections against it. Agar 2004 is important as perhaps the first book that uses the expression "eugenics" with a positive connotation coherently throughout. Agar endorses eugenics achieved by parents in a society which respects reproductive liberties since, unlike traditional eugenics, it is compatible with a pluralism of different conceptions about human flourishing.Savulescu 2001 argues that couples or single reproducers have a prima facie moral duty to select the embryo with the best life prospects, selecting against harmful genetic susceptibilities and in favor of beneficial ones. Wilkinson 2010 rejects the identification of "eugenics" and moral claims made in the context of the bioethical debate concerning pre-implantation genetic diagnosis and screening. He claims that it is wrong to the emotional power of "eugenic talk" to bypass rational critical faculties.