Update on preimplantation genetic diagnosis and screening

Recent advancement in both human embryology and genomics has created a completely new situation for practical and widespread application of preimplantation genetic diagnosis and screening with a dramatic effect on assisted reproduction. The mapping of the first human genome and the advancement in sequencing technology and bioinformatics has led to the discovery of the exact genetic background of exponentially increasing number of diseases. In parallel, methods for culturing human embryos have also radically improved, enabling the late transfer, and the procedure of vitrification the safe cryopreservation. In consequence, refined genetic analyses have become available from blastocyst biopsy followed by the application of novel genomic methods. Furthermore, some studies suggest that by the selection of aneuploid embryos the pregnancy- and birth-rates can be increased. The amount and the depth of information obtainable from the embryos raise several technical and ethical questions that can be answered by further prospective randomized trials.