Preimplantation genetic testing in assisted reproductive technology.

Preimplantation genetic testing is a methodology aimed at the assessment of the genetic composition of an embryo. This diagnostic approach has been used in assisted reproduction for almost thirty years. During these years, the technologies used for embryo's genetic analysis have been continuously improved allowing the development of more precise, comprehensive and robust strategies that are clinically employed nowadays. In this review, the main diagnostic approaches used for embryo genetic and chromosomal assessment are described and discussed both from an embryological and genetic standpoint.