It introduces highly specialized laboratory micromanipulation techniques with sperm, eggs, or embryos. During IVF, sperm, in a special solution, is added to retrieved eggs in a special media. The sperm have to penetrate the individual eggs by themselves (without any assistance).
In the case of men with normal sperm conditions (normospermics), approx. 50% of retrieved eggs are fertilized. Even in the case of normospermics, not every egg is reached by a quality sperm. It remains a matter of coincidence. Unfortunately, even an abnormal spermatozoon may penetrate the egg and fertilize it. However, in the fifth, seventh, or ninth week of the pregnancy, the embryo’s development stops. ICSI, PICSI or IMSI are methods which provide a solution to this problem by identifying quality sperm.