In vitro fertilization (IVF) is the process where sperm and egg cells are brought together in a laboratory environment for fertilization. The microinjection technique (ICSI) is a specialized form of IVF where a single sperm cell, obtained from the male partner, is directly injected into an egg cell, retrieved from the female partner, using a fine needle under a microscope. This method significantly increases the chances of fertilization and pregnancy, especially in cases of male-factor infertility.