A number of factors can cause or contribute to male infertility.

• Surgery to the reproductive tract, such as that for undescended testes, hernia repair, and or cancer
• Fevers and infections, such as mumps occurring after puberty
• Varicose veins in the scrotum (varicocele)
• Medical conditions such as diabetes
• Genetic or hormonal conditions
• Injury to the testes (physical or chemical)