Male infertility refers to a male's inability to cause pregnancy in a fertile female. A man's fertility generally relies on the quantity and quality of his sperm. If the number of sperm a man ejaculates is low or if the sperm are of a poor quality, it will be difficult, and sometimes impossible, for him to cause a pregnancy.
Male infertility is diagnosed when, after testing both partners, reproductive problems have been found in the male. Male factors account for at least 30 to 50 percent of all fertility issues in patients.