Infertility is the failure of a couple to become pregnant after 1 year of having regular, unprotected sexual intercourse. It can be caused by problems in a man's or woman's reproductive system.
Infertility is a problem for one of every six couples.
Most often a man is infertile because he produces too few sperm or no sperm at all. Sometimes the sperm are abnormal. That is, they are malformed and cannot swim properly or they have a short lifespan. A normal sperm has a lifespan of about 4 days. Sometimes the problem is the natural decline in fertility that comes with aging, especially after age 40.