Varicose veins of the testicle, known as varicoceles, are one of the more common causes of male infertility. Varicoceles are veins that have lost their ability to keep blood flowing briskly towards the heart. The one-way valves in these veins are leaky and blood flows less through them. They are more common on the left testicle because the veins from the left testicle have to travel a further distance than those on the right side and they connect into the main vein of the left kidney. The veins from the right testicle travel a shorter distance straight to the vena cava which is the main vein of the abdomen. Since the left veins have to travel further they have a greater risk of developing a congestion which can lead to stretched out, sluggish varicose veins. Varicoceles may cause the testicle to become too hot and then produce less sperm with less quality. Varicoceles often occur on the right side too, but usually not as severely. Both testicles are affected by a varicocele on just one side. Varicoceles are detected on a physical exam because they are abnormally prominent in the scrotum. Large varicoceles cause visible lumps in the scrotum and they have been described as feeling like a “bag of worms.” A Doppler ultrasound, which detects blood flow, can confirm the presence of varicoceles or help distinguish varicoceles from fatty tissue. Varicoceles arise during puberty and are present for the man’s lifetime. Even though they are often not discovered until a fertility evaluation, they have been present in that man since he was a teenager. On rare occasions a varicocele may be due to blockages on the vein drainage due to a tumor inside the abdomen which is pressing down on the veins. A careful exam by a specialist can determine when this is a possibility. About 15% of all men have varicoceles, but up to 40% of infertile men have them. Varicoceles are tricky because many normally fertile men may have varicoceles with no apparent affect on their ability to father a child. On the other hand, many infertile men are infertile because of varicoceles, and when the varicocele is treated they are able to father a child. Even so, there are a significant number of men who are infertile and have varicoceles but correction of the varicoceles does not improve their fertility. Varicoceles can cause the testicle to shrink in size and it may cause testosterone to decline. In some cases it causes pain. Some men may have a gradual decline in their fertility due to the varicocele such that they are able to father a child when they are younger adults but years later have difficulty. Correction of the varicocele is accomplished with either surgery or with interventional radiology. There are a variety of surgical approaches that all involve tying or clipping shut the abnormal veins as they travel away from the testicle into the lower pelvis. Because there are many veins and additional pathways that veins can grow to feed into the varicocele, the different approaches may or may not reliably get all the veins. The most reliable approach surgically is with an incision in the low groin (inguinal or sub inguinal) that is able to access the varicose veins as will as side feeder branches that may be going off into the groin or the scrotum. An operating microscope or magnifying glasses are used to enable the surgeon to see very tiny veins that are in the varicocele that should not be missed or the varicocele will come back. This is a same day surgery. The alternative approach is with interventional radiology where a catheter is maneuvered through the veins of the mans body until it reaches the varicose veins and then materials are released into the veins to clot them off. This technique does not work as well as surgery unless a specific protocol using a super glue like agent is used coupled with total body constriction so as to force the glue into the side feeder channels. The benefits from the treatment will not be measurable typically for about 6 months. Sperm counts may improve but not necessarily to normal, yet still enough for pregnancy to occur. Pregnancies typically occur 6 to 18 months after the surgery but may occur even after 2 years. This treatment is successful about 40% of the time. This compares with in-vitro fertility which has about a 40% success rate nationally. The risks of the treatment are very low and are on the order of about 1 to 2 percent. The risks include injuring the artery to the testicle which could make fertility worse and lower testosterone levels in the man. With the use of an operating microscope during surgery this is a very low risk. Even men with severely low sperm counts or even zero counts may potentially improve with treatment of their varicoceles. In some cases treatment will allow sperm to be present that previously was not and so allow a couple to go on to receive intrauterine insemination or in-vitro fertility when they otherwise many not have been able to. In a small number of cases, men with zero sperm counts can go on to father a child naturally after varicocele correction.