Until just a few years ago, genetic diagnosis of the embryo only allowed 9 of the 23 pairs of chromosomes to be studied. Thanks to array CGH, all 23 pairs of chromosomes can be examined in order to rule out any aneuploidies before implantation takes place. Aneuploidies are abnormalities in the number of chromosomes that can cause repetition faults in assisted reproduction cycles, spontaneous miscarriage and chromosomal anomalies in new-born babies. This technology makes it possible to identify which pre-embryos are healthy and which are not in the laboratory. CGH is recommended for patients who have suffered from repeated miscarriage, couples who risk presenting chromosomal abnormalities in their offspring, and also for female patients over the age of 40 who are planning to become pregnant using their own ova.