Male reproduction: anatomy, function & conception problems

A reminder of the basics

Millions of sperms develop daily in the testicles within a system of tiny tubes known as the seminiferous tubules. As sperm are produced, they pass from the testes to the epididymis, an organ that stores and nourishes sperm as they mature. The entire hormone-regulated process of sperm maturation, from their primitive beginnings in the seminiferous tubules to their fully mature form in the vas deferens, takes about 74 days. During intercourse a man releases semen, a combination of sperm from the epididymis and a fluid from the seminal vesicle and prostate glands. Sperm can live for 48 to 72 hours within the female reproductive tract, while retaining the ability to fertilize an egg.

Could I be the problem?

Conception difficulties are common. Almost one in ten couples have difficulties conceiving¹, but infertility is just as likely to be due to your partner’s health as your own. In fact 15-25% of cases involve both partners and 20% remain unexplained.² If you have concerns about your fertility, a good way to start is by talking to your GP. You may also consider seeing a urologist, or a fertility specialist such as an endocrinologist or an andrologist.

In men, the most common fertility issue is the production of sufficient normal, motile sperm. Here are some common problems men face that may inhibit conception.

Mumps

Contracting mumps after puberty may damage sperm-producing cells in the testicles. In most cases, only one testicle is affected. Some men suffer permanent sterility.

Varicocele

Varicocele is the presence of varicose veins around the testicles. It occurs when blood does not circulate out of the testicles properly. The increase in blood leads to a rise in the temperature in the testicles. This causes abnormal testosterone levels, which hinder the production of sperm.

Undescended testicles

As a baby boy develops in the uterus, his testicles typically form inside his abdomen and descend into the scrotum shortly before birth. When the move doesn’t take place, the baby is born with a condition known as cryptorchidism. Usually the testicles descend themselves by the sixth month of life. Untreated, undescended testicles may affect fertility or lead to other medical problems.

Testicular cancer

Testicular cancer is sometimes diagnosed when a couple is experiencing difficulties conceiving. A malignant tumour that develops in the testicle may destroy testicular tissue. If not detected early enough it may also spread to other parts of the body.

Diabetes

Diabetes has been found to have an effect on the quality of sperm.

Surgery or injury

Serious trauma to the testicles can affect the production of sperm and possibly lead to sterility. Damage from sport or by accident can rupture vessels that supply blood to the testicles. Additionally, surgery to correct an undescended testicle or repair a hernia may lead to damage of a man’s sperm-producing capabilities.

Physical abnormalities

In a small number of men, the fluid deposited in the vagina during intercourse may not contain sperm. This may be due to a blockage or malformation of the epididymis, which prevents the sperm from combining with other fluids to create semen.

Overheating

Heat can have a detrimental effect on normal sperm production. Too much time spent soaking in a hot tub can raise the temperature of the testicles and impair sperm production transitorily.

Too much stress, fatigue or alcohol

Overwork, anxiety and too many alcoholic drinks have a negative affect on libido. Until recently, most cases of impotence were thought to be psychological. However, new oral treatments offer widespread success.

^{1. Boivin J et al, International estimates of infertility prevalence and treatment seeking: potential need and demand for infertility medical care. Hum Reprod. 2007;22: 1506-1512.  2. Collins J.A. Evidence-based infertility: evaluation of the female partner. International Congress Series 2004;1266: 57–62.}