Varicose veins are enlarged veins, which can be found in many different parts of the body including the scrotum. A ball of varicose veins is called a varicocele in medical terms. There are many theories about the way varicoceles can affect fertility, but the most common is that these enlarged veins slightly increase the temperature of the testicles, which would reduce sperm quality. However, it is unclear if a varicocele actually contributes towards reduced fertility.

There is a controversy over the question of whether varicoceles do or do not affect fertility. Varicoceles can occur in fertile men. Therefore the treatment of them is also a matter of debate. Sometimes a slight improvement in sperm quality is indeed seen after treatment, but there is no improvement in the chances of an actual pregnancy.

Varicoceles can be surgically repaired by means of blocking the affected vein. Sufficient veins remain to ensure drainage of the blood. Closing off a varicocele in the scrotum is a relatively small operation for which different methods are available. An urologist can tie off the vein or a coil may be inserted into the vein by a radiologist, preventing blood flow through it.

If the sperm quality remains poor, or a pregnancy does not occur, assisted fertility treatments such as IUI, IVF or ICSI may be used.