Sperm disorder
Most common cause of male infertility deals with the production and development of sperm. This include azoospermia, a condition which produce no sperm cells and oligospermia, which produce few sperm cells.

Obstruction
This condition of blockage of sperm is caused by various reasons including prior vasectomy, injury, infection or physical anomaly. Any portion of the male reproductive tract, such as the vas deferens that carries sperm from the testicles to the penis or epididymis which stores sperms can be obstructed, preventing normal transport of sperm from the testes to the urethra, where it leaves the body during ejaculation.

Varicoceles
These are dilated scrotal vein or varicose vein in the testicle. It can damage the blood flow to the testes, making sperm production slowed or stopped. Sometimes these veins may be enlarged and twisted enough to be visible in the scrotum. This most correctable cause of infertility is usually discovered on physical examination.

Temperature can be a cause of infertility in men. Conditions that increase the temperature of the testes (where sperm are produced) can greatly reduce the number of sperm and the vigor of sperm movement and can increase the number of abnormal sperm.

Retrograde Ejaculation
This is a condition caused by the failure muscles or nerves of the bladder neck to close during ejaculation allowing the ejaculate to be propelled into the bladder instead of out the penis. Signs of retrograde ejaculation may be diminished or dry ejaculation and cloudy urine after ejaculation.

Others factors that can cause infertility include genetic disease such as cystic fibrosis or a chromosomal abnormality; certain medication such as anabolic steroids which may affect hormone levels and excessive consumption of alcohol can also interfere with sperm production.