Infertility is the inability to achieve a normal pregnancy. About one in seven couples in the United States is unable to conceive a child after trying regularly for one year. Some couples will have success in the second or third year of trying, but couples that cannot conceive after three years are very unlikely to ever succeed unless they seek medical assistance.
Infertility in a couple may be caused by the male partner, the female partner or both. Studies suggest the male partner alone is infertile in about 20% of cases and that both partners have fertility problems about 30% of the time. Therefore, the male partner plays a role in about half of all couples that have difficulty conceiving a child. In about 15% of cases, infertility tests are completely normal in both partners, despite the fact that the couple cannot conceive a child.
Male infertility has a wide variety of causes, which can be broken down into several major groups:
Hormonal problems, such as low levels of testosterone or thyroid hormone
Problems with the testicles, including abnormal growth or development, or damage from trauma and infections
Problems with the flow of sperm within the male reproductive organs, including blocked tubes that transport sperm, genital infections, varicose veins (varicoceles) within the scrotum, or problems with ejaculation
Abnormal sperm function
Inherited or chromosomal disorders, including cystic fibrosis and Klinefelter's syndrome
Exposure to toxins, such as radiation or industrial chemicals
Medications and drugs, including psychiatric medications, alcohol, and anabolic steroids used for body building
General illnesses, including kidney disease, cirrhosis and malnutrition
In up to 50% of infertile men, no specific cause can be identified.
In most cases, infertility is a harmless problem and may respond to treatment. However, about 1% of infertile men have serious medical problems (hormonal problems, infections or tumors) that require medical attention.