After a period of heated debate on the efficacy of PGS(Preimplantation Genetic Screening), followed by a cautious decline of the use of PGS, recent enthusiasm in PGS is evident.This renewed interest is facilitated, mainly, by several major factors: 1) The successful establishment of 24 chromosome detection platforms, such as aCGH, SNP array, and most recently,NGS (next generation sequencing); 2) The use of later stage biopsy when mosaicism may be lower than that at earlier stages and when more cells can be obtained so that test accuracy is likely increased;and 3) The demand from the patients who may have indications of carrying high risks of embryos with aneuploidy or the desire for single embryo transfer.Nevertheless, various opinions still exist and clear recommendations from professional societies are not yet available.