Spectacular progress in the therapeutic management of patients with severe male infertility was obtained with the implementation of intracytoplasmic sperm injection (ICSI) and has opened avenues to treating previously untreatable cases of infertility. However, it must be recognized that in the vast majority of ICSI cycles, the selection of the spermatozoon followed by the intracytoplasmic injection is done very quickly at low magnification and without detection possibilities for potential pathological morphological anomalies of spermatozoa. Strong correlations between sperm morphological characteristics and male fertility have been demonstrated. Thus, it seems reasonable to implement optimized non-invasive sperm selection techniques in ART based on morphological ’normalcy’ of spermatozoa. Almost 20 years ago, ’motile-sperm organelle morphology examination’ (MSOME) was introduced by Bartoov et al. Using Nomarski differential interference contrast optics (DIC) an improved three-dimensional view of the head and midpiece became available. This chapter will describe different aspects of sperm selection by morphology.

Application of intracytoplasmic morphologically selected sperm injection (IMSI) is a matter of debate; however, it is evident that deselection of spermatozoa presenting respectively spermatozoa with vacuole-like structures and asymmetrical insertion of the neck has multiple benefits. Defective sperm function and molecular defects contribute to early embryonic development disturbance, failure of blastocyst formation, miscarriages, and congenital birth defects. Introduction of IMSI has made embryologists aware that for ICSI the selection of sperm should be given proper attention. We have to consider IMSI has improved the ICSI technique. Compared to “blind” spermatozoa aspiration at low magnification and/or reduced optics contrast, observation under optimal contrast optics increases the probability of selecting a normal spermatozoa. This is particularly evident in cases of severe teratozoospermia, with low responder and advanced age women. Practicable and technical aspects of morphologically normal sperm selection must be considered to facilitate the workflow while performing IMSI and avoiding damage to the oocytes. A proper set up of the dish for selecting and capturing sperm facilitates routine application of IMSI.