“…In well-informed patients with lethal aneuploidy/mosaic embryos and no euploid options, transfer of aneuploid or mosaic embryos may be warranted. This view is based upon the present literature, suggesting that a diagnosis of an aneuploid/ mosaic Babnormal^embryo is not always correct, or if it is correct, mosaicism detected at the blastocyst stage may not manifest as such in a live born [29][30][31]. While testing methodology is able to identify definitely normal and grossly abnormal chromosome complements in most cases, there is a significant, not well-delineated, gray zone into which many chromosome-screening results fall, mostly attributable to the problem of mosaicism.…”