Infertility refers to the inability of a couple to achieve a pregnancy after attempting to do so for at least one full year. Infertility can be primary or secondary. Primary infertility occurs when a couple has never been able to conceive; secondary infertility describes a couple who have previously conceived a pregnancy, but are unable to conceive again after a full year of trying.

About 40% of the time infertility is due to a problem with the male partner; 40% of the time the problem is with the female partner; 20% of the time there are fertility problems with both the man and the woman in the couple; and about 3-4% of the time, no cause for infertility can be found.

The male contribution to fertilization and the establishment of pregnancy is the sperm. The sperm are mixed into a fluid called semen, which is discharged from the penis during a...