How does male fertility work?

Sperm are produced in the seminiferous tubules in the testes, which are also responsible for the production of testosterone, a male sex hormone, essential for male sexual functioning and fertility, amongst other things.

The process of sperm production, from the formation of germ cells, to fully mature sperm cells, takes about 70 days . When sperm development is complete, sperm are released from the seminiferous tubules and travel to the epididymis, where they become more mature and mobile. Sperm are stored in the epididymis until ejaculation, when contractions push a small amount of sperm into the vas deferens, through the prostate gland and into the urethra.

As the sperm travels down the reproductive tract, fluid is added by the prostate gland and seminal vesicles to produce semen. More than 90% of the ejaculatory fluid is produced by the prostate gland and seminal vesicles, which is why men who have had a vasectomy can still ejaculate normally.

In order for a man to be fertile, he needs to produce mature, healthy and mobile sperm in sufficient quantities to ensure the fertilization of the female egg. Ability to achieve and sustain an erection for long enough to ejaculate and deposit the sperm in the female reproductive tract is also important for natural conception.

Although there may be many causes of male infertility (genetic causes, infection, heat, tobacco, drug and alcohol abuse, sperm antibodies, inadequate testosterone production, poor nutrition, stress, scarring of the reproductive tract, some prescription drugs, pesticides and other chemicals and even hormones in meat and the food chain), no cause can be found in approximately 40% of men with fertility problems. This is called ideopathic infertility.