During the last thirty years preimplantation genetic testing has found diverse clinical application, expanding beyond the relatively small population of patients at high-risk of inherited disease transmission for whom it was initially intended. While the use of PGT has been highly successful in helping couples carrying gene mutations to reduce the incidence of affected pregnancies, it is now more commonly used for assessing chromosomal status of embryos generated during the course of routine IVF treatment. Chromosome abnormalities are extremely common in human IVF embryos and, in theory, the identification and preferential transfer to the uterus of euploid embryos should improve IVF treatment outcomes. Today, it is estimated that more than a third of all IVF cycles carried out in the United States utilise this type of testing to assist the selection of embryos, dwarfing the utilisation of PGT for other purposes. Recent technical developments suggest that PGT will provide patients with increasingly valuable reproductive strategies, while its growing capabilities may also pose ethical questions.