The inability of the male to effect fertilization of an ovum after a specified period of unprotected intercourse. Male sterility is permanent infertility.

Spermatogenic failure-6 (SPGF6) is a form of male infertility with globozoospermia. The acrosome is a unique structure of the mature spermatozoon, which plays an important role at the site of sperm-zonapellucida binding during the fertilization process. Globozoospermia (also called round-headed spermatozoa) is a human infertility syndrome caused by spermatogenesis defects (Lalonde et al., 1988, Singh, 1992). The most prominent feature of globozoospermia is the malformation of the acrosome and, in the most severe cases, the acrosome is totally absent. Globozoospermia is also characterized by abnormal nuclear shape as well as abnormal arrangement of the mitochondria of the spermatozoon (Battaglia et al., 1997). For a discussion of phenotypic and genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).