ABSTRACT
Treatment of severe male subfertility has become available since the intracytoplasmic
injection of a single sperm into an oocyte was successfully applied for the first
time in 1992. Moreover, with the use of fresh and cryopreserved epididymal and testicular
spermatozoa for this procedure, fertilization and pregnancies could be accomplished.
This review addresses the development and performance of these techniques and discusses
achievements and problems as well as future aspects of the feasibility of early spermatid
injection. Furthermore, limitations of these procedures and concerns with regard to
genetic and epigenetic risks of using immature gametes are stressed.
KEYWORD
TESE - MESA - ROSI - ELSI - cryopreservation - imprinting