A single centre observational study into the segmentation of preimplantation genetic diagnosis (PGD) treatment by comparing cumulative pregnancy rates following cryopreservation of all genetically transferable embryos after PGD, compared to fresh embryo transfer cumulative with frozen embryo transfer of genetically transferable embryos.The primary aim of the study is to assess the feasibility and effectiveness of segmentation in terms of pregnancy rates. The secondary aim is to assess the logistic advantage of segmentation in PGD cycles.