Current trends in evaluation of sperm function: in vitro selection and manipulation of male gametes for assisted conception

With increasing medical utilization of assisted reproductive technology (ART), scientists and clinicians have been able to study extensively multiple cell functions operating synchronously and flawlessly during the events preceding, before and after fertilization. Critical evaluation of the functional status of spermatozoa for in vitro techniques such as sperm-mucus interaction, acrosome reaction status, sperm-zona pellucida binding and penetration tests, hyaluronic acid binding assay, and computer assisted semen analysis etc. can direct a male partner of an infertile couple to more aggressive forms of treatments. In vitro selection of functionally competent sperm cells is a pre-requisite for successful outcome in in vitro fertilization or in intracytoplasmic sperm injection (ICSI). Direct injections of acrosome-intact spermatozoa into oocyte during ICSI bypassing the normal events of sperm oocyte interaction and fusion events have raised concerns with regard to fertilization abnormalities and genetic issues. The present communication briefly reviews the sperm function tests with emphasis on its correlation with fertility outcome, and the currently employed sperm selection and manipulation procedures which may have implications in assisted conception programs.