Assisted fertilization--treatment of severe male subfertility

Since 1992 direct injection of a single spermatozoon into the cytoplasm of the oocyte (ICSI) has developed as the treatment of choice in cases of severe male subfertility. The ICSI procedure displays high fertilization and pregnancy rates in cases of extreme oligoasthenoteratozoospermia. In combination with sperm aspiration from the epididymis or sperm retrieval by testicular sperm extraction, fertilization is possible even in cases of azoospermia. To date, a couple of thousand children have been born after ICSI. Despite the criticism about the lack of natural selection while breaking the zona pellucida and the cytoplasmic membrane with the injection pipette, there has been no increased incidence of malformations and chromosomal abnormalities.