A Man's Reproductive System

In men, the testicles are responsible for sperm production. Hormones regulate this production. Follicle stimulating hormone (FSH), lutenizing hormone (LH) and testosterone are all important for sperm production. Sperm mature in the epididymis which is coiled across the top of the testicles.

The mature sperm travel through the vas deferens, which are the tubes that carry the sperm from the epididymis to the penis. The seminal vesicles and the prostate gland add fluids to the sperm as they journey through the vas deferens.

The mixture of fluid and sperm is now called semen. The semen released during a single ejaculation contains up to 200 million sperm cells. The tails of the sperm cells propel the sperm through the vagina. Many of the sperm die in the vagina which is a relatively acidic and hostile environment for the sperm. The sperm have to make a tiresome journey through the vagina, pass through the cervix into the uterus and then into the fallopian tubes in search of the awaiting egg. If a sperm cell reaches the egg, it must then penetrate the egg cell so that the genetic material from the father and the mother can unite to create a new and unique organism capable of developing into a human being. Any disruption to these complex processes may contribute to infertility. The problems contributing to infertility in a man may be hormonal, chemical, or physical.