The use of preimplantation genetic diagnosis (PGD) has expanded both in number and scope over the past 2 decades. Initially carried out to avoid the birth of children with severe genetic disease, PGD is now used for a variety of medical and non-medical purposes. While some human studies have concluded that PGD is safe, animal studies and a recent human study suggest that the embryo biopsy procedure may result in neurological problems for the offspring. Given that the long-term safety of (...) PGD has not been clearly established in humans, this study sought to determine how PGD safety is presented to prospective patients by means of a detailed website analysis. The websites of 262 US fertility centres performing PGD were analysed and comments about safety and risk were catalogued. Results of the analysis demonstrated that 78.2% of centre websites did not mention safety or risk of PGD at all. Of the 21.8% of centres that did contain safety or risk information about PGD, 28.1% included statements highlighting the potential risks, 38.6% presented information touting the procedure as safe and 33.3% included statements highlighting potential risks and the overall safety of the procedure. Thus, 86.6% of PGD-performing centres state that PGD is safe and/or fail to disclose any risks on their websites despite the fact that the impact of the procedure on the long-term health of offspring is unproven. This lack of disclosure suggests that informed consent is inadequate; this study examines numerous factors that are likely to inhibit comprehensive discussions of safety. (shrink)

In 1971, Günter Blobel and David Sabatini proposed a novel and quite speculative schematic model to describe how proteins might reach the proper cellular location. According to their proposal, proteins destined to be secreted from the cell contain a “signal” to direct their release. Despite the fact that Blobel and Sabatini presented their signal hypothesis as a “beautiful idea” not grounded in experimental evidence, they received criticism from other scientists who opposed such speculation. Following the publication of the 1971 model, (...) Blobel persisted in conducting experiments and revising the model to incorporate new data. In fact, over the period of 1975–1984, Blobel and colleagues published five subsequent schematic models of the signal hypothesis, each revised based on new laboratory evidence. I propose that the original 1971 model can be viewed as an epistemic creation. Additionally, analysis of the subsequent schematic diagrams over the period of 1975–1984 allows one to track Blobel’s changing conception of an epistemic object over time. Furthermore, the entire series of schematic diagrams presented by Blobel from 1971 to 1984 allow one to visualize the initial conception and subsequent reworking of a scientific theory. In 1999, Blobel was awarded the Nobel Prize in Physiology or Medicine for his work on the signal hypothesis, which was ultimately supported by experimental evidence gathered after the speculative model was published. (shrink)