What are the known causes of male infertility?
Male infertility can be caused by problems that affect the sperm production or the sperm transport process. With the results of medical tests, the doctor may be able to identify a cause of the problem. Known causes of male infertility can be described as: • Hormonal problems Sometimes the pituitary gland at the base of the brain does not send the right messages to ‘drive’ (stimulate) the testes. This can cause low testosterone levels, which means that sperm are not produced. Hormonal causes are uncommon, and affect less than one in 100 infertile men. • Sperm production problems The most common cause of male infertility is due to a problem in the sperm production process in the testes. Low numbers of sperm are made and/or the sperm that are made do not work properly. About two thirds of infertile men have sperm production problems. • Blockage of sperm transport Blockages (obstructions) in the tubes leading sperm away from the testes to the penis can cause a complete lack of sperm in the