The PGT study can only be conducted on embryos created by in vitro fertilization. Moreover, it is important to have a good number of embryos, since the abnormal ones will be disposed of after the study and only those diagnosed as normal for the purpose of the study will be transferred. For conducting the PGT, it is better that the embryos are cultivated until the blastocyst stage, which is attained on the 5th-6th day after fertilization. This is the moment when the embryo reaches an internal cellular mass that will develop to form the fetus, as well as another external layer called trophectoderm, which will go on to form the placenta. The Embryo Biopsy is conducted on the latter. Embryo Biopsy is the technique that permits making a small orifice in the trophectoderm of the embryo to aspirate 4-5 cells with a micropipette. Since these cells will develop to form the placenta, if the technique is carried out properly, it should not affect the development of the fetus. Once the biopsy has been carried out, the embryo is vitrified or transferred after learning the result of the study.