The fertility of a male partner is often taken for granted - but many factors such as heat, drugs, age, smoking, infections and lifestyle can affect a man’s ability to father children.

A recent study carried out in the UK by Bunting and Bolvin revealed some startling facts about the knowledge that young people in that country have about the factors that can impact on human fertility.

As a result of their study, these researchers concluded that young people are aware of many of the negative lifestyle factors that can reduce the ability for a couple to conceive. However, they falsely believed in what could best be termed "Fertility myths" - such as the benefits of certain healthy habits. For example, those who were surveyed wrongly believed that abstaining from certain things - for example, not drinking alcohol or not urinating after having sex - could increase the chances of the woman becoming pregnant.

Despite popular opinion that failure to conceive is usually due to female (gynaecological) problems, statistics show that in about one in five infertile couples the infertility is due to problems relating to the male partner.

While there are some causes of male infertility that cannot be prevented (like poor sperm production) there are several things that a man can do to protect his fertility.

Infections, particularly sexually transmitted diseases like chlamydia and gonorrhoea, can result in obstruction to the Vasa deferentia (the tubes that carry sperms from the testes to the seminal vesicles). Although surgery can be done to remove such an obstruction and rejoin these tubes, such surgery is not always successful.

Mumps is a viral infection that can affect males at any age - but it is more serious in its consequences if it affects males after the age of puberty. The mumps virus can permanently damage the cells that produce sperms by infecting these cells. Mild infection with mumps can also stop sperm production, although this is only for a period of half to one year.

Similarly, urine infection can spread from the bladder into the epidydimis and testes (a condition referred to as Epidydimo-orchitis) and in rare instances even cause permanent damage to these organs.

Prescribed drugs like some antidepressants, sedatives and the anti-inflammatory drug Salazopyrin that is often used to treat auto-immune diseases, are known to cause long term fertility problems in some men. Illegal drugs like anabolic steroids can actually shrink a man’s testes and stop sperm production - as can illicit drugs like marijuana (ganja) and heroin which reduce a man’s level of testosterone and lower his sex drive.

Cigarette smoking affects male fertility, with heavy smokers known to produce up to 20 per cent fewer sperms than non-smokers. Smoking can also increase the quantity of abnormal sperms because the genetic material (DNA) in sperms is damaged by some of the chemicals contained in tobacco smoke.