 1. Control group: All blastocyst embryos will be biopsied on day 56, but the biopsies will be frozen and will not be analyzed before replacement. Blastocyst embryos will be vitrified for future frozen embryo transfer FET cycle. Patients will have a single hatching blastocyst thawed and transferred into the uterus in a FET cycle based on standard embryo quality assessment without NGS. After transfer, all biopsied samples will be analyzed the replaced embryo also, in order to do a non-selection study. If patients in the control group do not have a pregnancy to term from that FET cycle, euploid frozen blastocysts will be thawed and transferred on the next FET transfer. 