How do varicoceles cause male infertility – Dr. Vasan S S

Varix means violation or ballooning of a particular Part, so in this case there is balooning of viens which are around testis, now technically what does the vein do, it pumps the blood back from the testis towards the heart.Ans since man is standing most of the time so it has to work anti gravity unlike a gravity which has a muscular compartment, vein does not have muscels, So the challenge is vein balloons, it loses efficiency and its causes pooling of blood, so if you can imagine what does a pooling of blood do? if you have a minor injury, a small boil, a small Hematoma or a bluish black patch, so when the blood accumulates because of the ballooning of the vessels around testis it causes stasis that means stagnant blood and it does not have oxygen. And secondly blood being warm, it increases the temperature around the testis. For sperm production testis is placed outside the body cavity only because it requires a lower temperature of 1 to 2 degree lesser than the body temperature. So effectively we change that mechanism when this ballooning of vessels happen and also the temperature rises and there is pooling of blood which causes lack of oxygen, consequent to that there is a change in the neuronal chemical released and all these effects sperm production by either decreasing the sperm production or making the sperm production abnormal.

Source: How do varicoceles cause male infertility – Dr. Vasan S S