From modern technology to tight pants, many things are said to affect a man's sperm count. With the help of some experts, we separate the facts from the fiction.
Maintaining a healthy sperm count can be tricky, with stress, regular use of technology and obesity just three examples of the factors commonly listed as potential causes of male infertility.
But do these and other factors really affect the sperm count of the modern man? How big a threat do they pose to male fertility? And which are simply old wives tales with no basis in scientific fact?
We've consulted the experts to separate the myths from the the reality.
All too often, fertility problems are seen as a female issue. "Male fertility problems certainly aren't given enough exposure; much of the focus is with the woman, but the male factor represents 50 per cent of the cause of fertility issues," points out fertility clinic worker Shaheen Hashmat.
"Additionally, although only one sperm is needed to fertilise an egg, and specific procedures such ICSI (intracytoplasmic sperm injection, where the sperm is injected into the egg) can be used to overcome issues such as low sperm count or motility, the quality of that sperm is also very important."
The effect of mobile phone use on sperm count remains a hot topic, and while there is currently no hard scientific proof that the two are connected, recent studies suggest that prolonged use certain types of computers and laptops can affect sperm count.
"Recent reports suggesting that carrying and using mobile phones on a daily basis can reduce male fertility have yet to be scientifically validated," says a spokesperson at London-based fertility clinic The Bridge Centre. "However, recent studies suggest that prolonged use of laptop computers especially those with infrared connectivity may have an adverse effect."
Sexually transmitted diseases
Although studies have failed to prove that sexually transmitted diseases have a direct effect on sperm count, many such infections can lead to conditions which do.
"While initial reports don't show a decrease in sperm motility and count by direct contact with STDs, gonococcal and chlamydial infections can lead to prostatitis and epididymitis, which can then cause obstruction of the ductal system leading to impaired fertility," says Dr Larry Lipshultz, a world-renowned expert in male fertility and founder of the website infertility-male.com.
It's thought that hot baths, regular Jacuzzi use and high central heating temperatures can all affect sperm production.
Although we're not suggesting restricting all future holidays to locations within the Arctic circle, studies have shown that regular exposure to high temperatures can affect sperm count. "Try to keep your testicles cool," suggests Shaheen at Zita West. "Sperm production occurs at three to four degrees lower than body temperature."
If you've got a penchant for tight pants, the good news is despite the popular urban myth, there's little research to suggest that your love of budgie-hugging underwear will leave you infertile.
"Most studies comparing loose boxers v tight briefs do not show a significant effect on semen quality," points out Larry Lipshultz. "In clinical practice, the type of underwear does not appear to have a significant effect."
We all know that being overweight isn't great, but the bad news is that having a high body mass index (BMI) can have a huge effect on male fertility.
"Being overweight can increase the temperature of the testicles through the formation of fat deposits in the groin area, but can also increase the level of oestrogen circulating in the body," warns Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield's Academic Unit of Reproductive and Developmental Medicine.
"Both of these will make the testicles work less efficiently. In general if men have a BMI greater than 30, they are three times more likely to be sub-fertile. However, there is no evidence that losing weight will improve matters - that study hasn't yet been done."
In the same way that we all know being overweight is bad, it's common knowledge the cancer sticks aren't exactly a quick route to a long life either.
However, cigarettes also lower many of the key ingredients that sperm need to function. "Smoking isn't healthy under any circumstances and tobacco smoke contains chemicals that weaken sperm function and deplete the antioxidants, especially vitamin C, that neutralise the damaging free radicals," reveals a spokesperson at The Bridge Centre. "Give up right now is the only advice you need."
The bad news is that alcohol has an immediate effect on sperm count. The good news? Giving your body a significant break from alcohol can quickly correct the situation.
"A heavy social drinking session will temporarily reduce your sperm count and regular heavy drinking damages the tubes that carry semen, reduces motility and increases the numbers of abnormal sperm cells," warns a spokesperson at The Bridge Centre. "Giving up alcohol completely for three to six months can, on its own, be sufficient to restore fertility if you drink heavily and have been doing so for some time."
It shouldn't come as a huge surprise that making a baby involves having sex. But what many men fail to realise is that regular sex also helps to maintain a high sperm count.
"If you're trying for a baby, forget about the big focus on her 'fertile' time," suggests Shaheen Hashmat. "You need to be having sex at least every two or three days. You do not need to save up the sperm if you abstain from sex, the proportion of dead sperm will increase. The key thing is to make sure there is a good supply of fresh, healthy sperm at the ready."
Long hours at work or stress in your private life can have a disastrous effect on sperm count.
"Stress at work or home leads to high levels of adrenaline and the release of other hormones which can restrict blood flow to the testes and inhibit sperm production," explains a spokesperson at The Bridge Centre. "Stress can also lead to the release of chemical by-products, known as free radicals, which damage sperm."
When it comes to maintaining a healthy sperm count, it should come as no surprise that recreational drugs should be avoided at all costs.
"Cannabis leads to a lowered sperm count and an increase in abnormal sperm," says a spokesperson at The Bridge Centre. "Smoking one joint lowers testosterone levels for up to 36 hours while cocaine negatively affects sperm motility and inhibits fertilisation. Avoid muscle-building drugs, too. Anabolic steroids may boost sex drive in the short term but, in the long term, they have the opposite effect and can cause a significant drop in sperm count."
Find out more
If you're worried about your sperm count or fear there might be a problem, a simple test at a fertility clinic could put your mind at rest.
"Have a semen analysis done by a fertility clinic," suggests Barbara Collura, executive director of RESOLVE, the largest infertility charity in the US. "If you're not registered with a fertility clinic, have a semen analysis done by a urologist. This is the best way to determine if you will have any issues."