The testicles are the male reproductive organs that serve as a part of both the nervous and reproductive systems, acting as the ovaries’ counterpart. The testicles work to produce sperm and introduce chemicals such as testosterone.

Formation and Orientation

There are normally two testicles in the average male anatomy. These can be found in the protective sack called the scrotum.

Two phases mark the growth of the testicles. During the embryonic stage, there is a possibility of this reproductive organ developing into either ovaries or testes. Through various stages of the embryonic phase, the testicles develop more. At week six, sex cords begin to form. This leads to the accumulation of the Y-chromosome which determines the fetus to be male. By the end of the embryonic phase, testes should have followed the “path of decent” which is the migration of the testes from the posterior fetal abdomen to their final place in the scrotum.

In the pubertal phase, sperm begins to be produced which allows for reproduction later on.


Both the production of spermatogenesis and testosterone are caused by hormones given off by the anterior pituitary gland. Both testosterone and follicle-stimulating hormones are needed for sperm production.

The sperm that is produced in the testes is then sent through the coiled epididymis tube to mature. After maturing, it is sent through the deferent duct, the spermatic cord to the vas deferens, through the urethra and expelled through ejaculation. This organ is absolutely necessary for reproduction.

Image Caption: Testicles. Credit: Wikipedia