The oocytes obtained after the egg collection process are evaluated.

After the immature or degenerated oocytes are sorted, mature oocytes (MII oocyte) are waited for approximately 4 hours. Again on the same day, the partner of the patient gives semen. Semen is prepared after passing through washing processes.

A driblet containing 100.000 sperms is left around each oocyte and the sperms and oocyte is gathered together. Only one sperm cell (spermatozoon) can enter into each oocyte. After the spermatozoa passes through the outer membrane around the oocyte called zona pellucida, the membrane is no longer permeable to another sperm. Therefore, other sperm cells cano not penetrate the outer membrane of the oocyte. As a result of this natural selection process, only one of the 100.000 sperms can penetrate the membrane and fertlize the egg. In Conventional IVF approximately 70% of the eggs are fertilized.

The outer layer surrounding the egg consists of corona radiata and zona pellucida mebrane. While a spermatozoon is penetrating these layers, its outer sheat and tail is left outside. Only the nucleus part, carrying the genetic material of the spermatozoa is admitted inside the cytoplasm of the oocyte. The unification of the sperm and the egg is like this via Natural ways or in Conventional IVF. The outer embrane of the oocyte uniting with a spermatozoon serves the function of a shield and a second spermatozoon can not enter into the egg. However in ICSI whole of the spermatozoon is injected inside the egg.