Today, we shall be comparing and contrasting IVF, which is in vitro fertilization, with ICSI, ICSI or intracytoplasmic sperm injection. The first ICSI baby was presented to the world by professor Paul Devroy and professor Andre van Streatijim in 1992 in Belgium. Now in this class, we the learning objectives will be about physiology of fertilization, why there is failure, how is IVF different from natural cycle, and how is ICSI different from IVF? And finally, is there any evidence for using ICSI over IVF in non-male factor infertility? This is a very similar slide about physiology of fertilization. On the left side, you can see the normal process of fertilization, which involves sperm transport, capacitation or sperm activation, acrosome reaction or dissolution of the zona pellucida, and on the maternal side, on the woman's side, oocyte activation, which involves the calcium channels, and finally, phosphorylation. So all these things need to happen during the fertilization of the sperm with the oocyte. The capacitation and acrosome reaction occurs in the natural fertilization. The penetration of cumulus oophorus and zona pellucida. The zed p three glycoprotein requires activation of signaling pathways, and this is known as capacitation. In turn, capacitation is necessary for acrosome reaction. So these steps imply further selective pressure on the sperms. So it follows that those sperms that lack the signaling mechanisms cannot or do not reach the oocyte in natural fertilization. Again, it is the selection of the fittest in the sense those sperms that are capable of having these signaling mechanisms are the ones that reach the oocyte. Visit: https://www.iirrh.org/fellowship-in-reproductive-medicine.php