Fig. 1

Schematic representation of in vivo and in vitro steps of mammalian fertilization. I Ovarian hormonal stimulation promotes follicle maturation and then ovulation. II ART uses different fertilization techniques to achieve fertilization, while in vivo female and male gametes interact and fuse in the female tract (infundibulum). III After fertilization, the preimplantation embryo spends a time under cultured conditions that may affect its further development. IV During this period of time, different techniques such as preimplantational embryo biopsies can be applied. V Finally, the in vitro produced embryo is transfered to a recipient female. On the other hand, the developing embryo moves towards the uterus interacting with the female reproductive system in a optimal environment