Too much information? The paradox of enlarging genetic datasets for human embryo assessment during in vitro fertilization (IVF)

Preimplantation genetic diagnosis (PGD) enables genetic diagnosis of embryos derived from in vitro fertilization (IVF), with the purpose of avoiding the transmission of genetic diseases to offspring. PGD represents an alternative to prenatal diagnosis and termination of pregnancy in couples at risk for transmitting these disorders. Since the first PGD application (Handyside et al., 1990), it has been made available for a large number of rare genetic disorders, and the number of cycles increases annually (Harper et al., 2010). PGD can be performed today for any genetic disorder when the specific gene and/or familial mutation is known. Furthermore, it is performed for chromosomal abnormalities (carriers of balanced translocations, inversions, and ring chromosomes) using new technologies (microarray and next-generation sequencing) for chromosome copy number assessment (e.g., aneuploidy testing, preimplantation genetic screening). The question regarding whether to allow or even suggest PGD for people at risk for nonlethal conditions in offspring has begun to emerge in the medical community. In the early days of PGD practice, it was clear that the main aim of the technology was to prevent lethal childhood-onset conditions (i.e., Tay-Sachs, spinal muscular atrophy, thalassemias).