Drinking, smoking or being overweight 'does not harm men's fertility'
Men with unhealthy lifestyles 'likely to be just as fertile' as those living more sensibly
23:42 GMT, 12 June 2012
NHS guidelines say GPs are supposed to warn men diagnosed with infertility of the dangers of alcohol, tobacco and recreational drugs
It's the advice every man trying to become a father wants to hear – have a drink and relax.
Researchers said yesterday that they have evidence that it probably won't harm their chances of starting a family. Nor will smoking, taking drugs or being overweight.
They found men with unhealthy lifestyles were likely to be just as fertile as those living more sensibly.
Under NHS guidelines issued in 2004, GPs are supposed to warn men diagnosed with infertility of the dangers of alcohol, tobacco and recreational drugs.
To try to improve sperm quality, infertile men are also urged to avoid being overweight and not to wear tight underwear.
The quantity of 'swimming sperm' available is regarded as critical to attempts to conceive, and infertile men are advised to cut out unhealthy habits to improve it. This leads to extra strain for many childless couples at an already stressful time. But a British study suggests many factors that were thought to contribute to sperm problems have little impact.
Estimates suggest around 30 per cent of men in couples seeking IVF treatment are subfertile, and 2 per cent are 'totally' infertile, while some studies show dramatic falls in average sperm counts. In some cases, fertility treatment is delayed or withheld on the NHS until couples improve their lifestyles.
However, the number of swimming sperm a man produces appears virtually unaffected by lifestyle choices, claim a team of scientists from Manchester and Sheffield universities.
They recruited 2,249 men from 14 fertility clinics around the UK and asked them to fill out detailed lifestyle questionnaires. Information from 939 of the men who produced low numbers of swimming sperm was then compared with information from 1,310 who produced higher numbers.
The results, reported in the journal Human Reproduction, showed that men with poor quality sperm were 2.5 times more likely to have had testicular surgery, and twice as likely to be of black ethnicity.
They were also 1.3 times more likely to do manual work, not wear loose boxer shorts, or not to have had a child before. But men's use of tobacco, alcohol and recreational drugs made little difference.
Around 30 per cent of men in couples seeking IVF treatment are infertile
Even being overweight, as measured by body mass index, did not affect sperm quality. The number of swimming sperm broadly correlates with how fertile a man is likely to be. It also often determines the type of fertility treatment that is offered. Study leader Dr Andrew Povey, of Manchester University, said: 'Our results suggest that many lifestyle choices probably have little influence on how many swimming sperm they have.
'For example, whether the man was a current smoker or not was of little importance. Similarly, there was little evidence of any risk associated with alcohol consumption.
'This potentially overturns much of the current advice given to men about how they might improve their fertility.'
Co-author Dr Allan Pacey, senior lecturer in andrology at Sheffield University, said men should still take care of themselves, without feeling the need to 'become monks'.
But he added: 'Although we failed to find any association between common lifestyle factors and the number of swimming sperm, it remains possible that they could correlate with other aspects of sperm that we have not measured.
These include the size and shape of sperm or the quality of the DNA.'