When a testicle does not descend into the scrotum, the condition is called cryptorchidism. It is a birth defect and is associated with infertility. However, if a man has only one undescended testicle, his ability to father children is almost equal to that of men without cryptorchidism.
When cryptorchidism is diagnosed in early childhood, surgery to move the testicle from the abdomen into the scrotum should be performed within the first year. This can prevent later infertility and reduce the risk of testicular cancer. If an adult has an undescended testicle, surgery can optimise testosterone production.
Abnormal cell growth in the testicular tissue affects sperm production. So does cancer treatment. Testicular cancer is mostly seen in younger men and is associated with poor semen quality, cryptorchidism and in families with a history of testicular cancer.
Treatment is surgical removal of the testicle. Sometimes additional chemotherapy will be used, which can also lower semen quality. If a man wants to father children in the future, a semen sample should be collected and preserved before surgery.
Varicocele is enlargement of the veins that drain blood from the testicles. The condition affects about 2 in 10 men and is seen in a quarter of men with abnormal semen analysis. The enlargement of these veins can be uncomfortable and can lower sperm quality. It is not fully understood how varicocele affects fertility.
Varicocele can be diagnosed easily by physical examination or by ultrasound. The treatment is surgery to close the dilated vessels and minimize blood reflux into the scrotum. Surgery can improve semen quality if no other explanation of infertility is found.
Infections in the male reproductive organs
Infections in the urethra, prostate, epididymis, and testicles are all potential causes for infertility. The infection creates antibodies that can lower semen quality. This can have a negative effect on fertility. When the location of the infection and the bacteria are identified, the treatment is mostly antibiotics.
Nevertheless, in almost half of cases, it is not possible to find a cause of infertility.