The proportion of men suffering from subfertility has increased and sp
erm quality of the general population has decreased rather dramaticall
y during the last decades. Conventional methods to measure sperm conce
ntration, motility, and morphology give a rough estimate of the fertil
izing capacity of semen. Objective assessment of motility characterist
ics and morphometric image analysis may give more precise information,
but technology still needs to be refined. Some aspects of the functio
nal capacity of spermatozoa may be impaired before measurable changes
occur in their number or morphology. A battery of tests is described t
o evaluate sperm migration and capacitation, acrosome reaction and acr
osin activity, zona adhesion and binding, sperm oolemma fusion, sperm
head decondensation, and chromatin make-up. Also methods are described
to localize the possible site of impairment of the genital tract. Imp
lementation of these methods may enhance our capability to detect mino
r effects of environmental hazards on male reproductive health.