In the last decade, preimplantation genetic testing have become widely used and in 2005 constituted 5 percent of all in vitro fertilization cycles performed in Europe. Their diffusion, however, is not homogenous; while in some countries they are prohibited and in others hardly implemented, Spain performs 33 percent of all the PGD/pgs. While policy guidelines and mainstream bioethics address PGD from a patient choice perspective, disability studies insist on PGD’s potentiality for discrimination. Alternatively, other authors have explored PGD/pgs from the (...) perspective of geneticization but little work has been done on how PGD/pgs are framed by the members of national regulatory bodies. Combining the analysis of juridical documents with semistructured interviews with members of the Spanish National Assisted Reproduction Committee, this study suggests that the remarkable diffusion of PGD/pgs in Spain may be largely due to the interaction between the growing momentum enjoyed by embryonic stem cell research and a vibrant expansion of IVF business along the Mediterranean coast. In this process, genetic issues per se seem to play a minor role, although the prevention of genetic diseases now constitutes the master narrative underpinning the extension of PGD from monogenic, early onset, diseases to polygenic, late-onset, ones. (shrink)