Preimplantation embryo aneuploidy is a major source of adverse outcomes in human reproduction since it leads to implantation failure, early pregnancy loss or severe chromosomal diseases. The risk of embryos aneuploidy is drastically increased after 35 years old. The intra uterine transfer of euploid embryos assessed through such techniques as next-generation sequencing (NGS) based Comprehensive chromosomal Testing of Trophectoderm (TE) biopsies of Blastocysts (CTTEB), may improve implantation and live birth rates, and decrease miscarriage rates. But no randomized controlled trial (RCT) was ever performed to test the interest of CTTEB for women that really needed it (≥35 to ≤ 41 years old). In this multicentre randomized-controlled-trial, the investigators will compare live birth rate obtained after the first single frozen-thawed blastocyst transfer cycle following the freeze-all-Intracytoplasmic sperm injection cycle in infertile and old couples between two different strategies of Day 5/6 blastocyst selection: * Control group: morphological criteria (Istanbul consensus) * Interventional group: international recommendations after CTTEB (www.pgdis.org; Newsletter May 27, 2019).