This chapter establishes fertility/subfertility thresholds for sperm concentration, motility, progressive motility, and sperm morphology using Tygerber strict criteria. It seems as if the sperm morphology threshold of 0-4 percent normal forms indicates a higher risk group for subfertility and fits the in vitro fertilization (IVF) and intrauterine insemination (IUI) data calculated previously. A concentration of below fifteen million per ml and percent motility below 30 percent also reflect parameters in the subfertile range. Swim-up and sperm functional tests must be encouraged to assist clinicians in the day-to-day handling of male factor infertility and be of immense help to make a good decision on a specific male problem. It is estimated that intracytoplasmic sperm injection (ICSI) should be indicated when male infertility is properly diagnosed based upon a state-of the- art extended evaluation of the male partner and also in cases with previous failed fertilization.