The brief answer is that the discharge of semen from the...

The brief answer is that the discharge of semen from the human body is not an act that is restricted to just one part of the body (unlike urine and other body wastes), a claim which is substantiated by the fact that the effect of the discharge becomes manifest on the entire body. Subsequent to a discharge, all the cells of the body slip into a characteristic lethargy; which is an indication of its effect on all the parts of the body.

Explanation Studies conducted by scientists reveal that within the human body there exist two vegetative nervous networks which control and regulate all the activities of the body. These two nervous networks - the sympathetic nerves and the parasympathetic nerves - are spread out throughout the body and around all the internal and external systems and tracts.

The function of the sympathetic nerves is to accelerate and stimulate the activities of the various tracts of the body, whereas the parasympathetic nerves function to decelerate and diminish them. In effect, one plays the role of the accelerator of an automobile while the other plays the role of the brakes; with a balanced functioning of these two sets of nerves, the systems of the body work in a balanced and normal manner.

At times certain occurrences in the body disrupt this balance and equilibrium - one of these being the issue of 'orgasm', which is usually contemporaneous with a seminal discharge. In such cases, the parasympathetic nerves (the decelerating nerves) tend to take a lead over the sympathetic nerves and consequently disrupt the equilibrium, negatively.

It has also been established that amongst the things that could force the sympathetic nerves into activity and re-establish the lost equilibrium is contact of water with the body, and since the effect of orgasm is noticeably felt on all parts of the body and the equilibrium existing between these two sets of nerves is disrupted all over the body, hence it has been ordered that after sexual intercourse or seminal discharge the entire body should be washed with water so that as a result of its regenerative effect, equilibrium is once again established between these two sets of nerves all over the body.[^5] Of course, the benefits of ghusl are not just confined to the above for, in addition to this, it is also a form of worship whose ethical influence cannot be denied.