What causes Infertility in Men? Male infertility is a condition in which a man has difficulty or inability to father a child due to problems with his reproductive system. This can be due to a variety of factors that affect the quality, quantity, or movement of sperm. Infertility is defined as the inability to conceive a child after one year of unprotected intercourse. In approximately one-third of couples who struggle with infertility, the cause is attributed to male factors, such as low sperm c