London - As many as one in six couples will have difficulty conceiving - and what most people won’t realise is that in about half of such cases, the problem is due to the man.
In recent years, a number of studies have suggested the situation is getting worse, with sperm counts falling, prompting some experts to warn that male fertility is in crisis.
A major French study published a year ago found that average sperm counts fell by one third between 1989 and 2005.
The researchers at the Institut de Veille Sanitaire in St Maurice tested samples from 26 000 men.
At the beginning of the study, the average for a 35-year-old man was 73.6 million sperm a millilitre; by 2005, it had dropped to 49.4 million per ml. Anything below 20 million is considered low.
An earlier analysis of 101 studies found that the proportion of men with a sperm count below 40 million a ml increased from 15 percent in the 1930s, to 40 percent in the 1990s through to 2009.
The link to life expectancy
The implications go beyond infertility and the psychological distress suffered by childless couples, since sperm count is considered a barometer of general health and a predictor of life expectancy.
As Richard Sharpe, professor of male reproductive health at Edinburgh University and one of the country’s leading experts on male fertility, puts it: “The present situation is not good for men.” What could be behind the problem? “We know that what happens while a baby boy is in the womb is critically important in terms of determining his future testosterone and sperm count.”
In this case, if a mother’s lifestyle during pregnancy (smoking or drinking, for example) may be partly responsible, a father’s behaviour before conception may also play a part. Diet and lifestyle can alter the way our genes work (a process known as epigenetics), and this in turn can have knock-on effects for future generations.
Why your grandad may be to blame
A study published last year in the journal Human Reproduction showed when male mice were fed a high-fat diet, their babies suffered fertility problems, their sperm had more DNA damage and they fathered fewer babies. (Female offspring’s fertility was also affected.)
The pattern continued in the next generation of mice.
In other words, if you eat too many fatty foods, your children – and even your grandchildren – may be infertile.
“It raises an interesting speculation, that it’s the change in the diet of our fathers and grandfathers causing current male fertility problems, says Sharpe
“We need to find out if there’s any truth in that, because if there is, we really would be looking at a ticking time bomb. Various factors in our modern lifestyle, diet or environment are undoubtedly making the situation worse.”
This year, a Danish study of 953 men found those who suffered disturbed sleep had sperm counts more than a quarter lower than normal.
This may be because the factors that interfere with good sleep such as obesity, a high-fat diet, diabetes and excessive alcohol are also linked to low sperm count.
The increasing number of chemicals in our environment might be another factor, suggests Dr Simon Fishel, managing director of the CARE Fertility clinic group and a leading specialist in fertility treatment.
There’s been much focus on bisphenol A, a chemical used widely in products such as plastic food containers and tin cans. In 2010, a study of more than 500 Chinese men found that those with higher bisphenol A levels in their urine were two to four times more at risk of having low sperm concentration and quality.
The fear is that regular exposure to bisphenol A disrupts hormones, changing the way sperm is made.
Men leave it too late to conceive
Not everyone is convinced by the bisphenol A effect: many experts argue that we are exposed to such small levels of the chemical that it could not possibly do any harm. There’s little doubt, though, that smoking affects fertility; alcohol may do too.
While lifestyle factors are implicated, however, the question is whether it is sperm count or sperm quality – the shape of the sperm and its ability to function – that is more important.
Sheena Lewis, professor of reproductive medicine at Queen’s University Belfast focuses her work on DNA – the genetic blueprint – of sperm, which is crucial to it working at its best.
“If you have 500 million sperm an ejaculation, but each one has DNA damage, then it’s not probable it will make a baby,” says Lewis.
Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield believes that the discussions about sperm counts, cling film and waist lines are just a distraction from a far bigger and more scientifically credible problem: men are leaving it too late before they try for fatherhood.
His team compared the lifestyles of 939 men with poor sperm quality with 1 310 men with normal sperm quality.
“There was no effect from body mass index, smoking, alcohol or recreational drugs,” he says. “The only thing we found to be a risk was tight boxer shorts.” (Tight underpants raise the temperature of the testes, which negatively affects sperm production.)
“Twenty or 30 years ago, if you were an infertile man trying for a baby, you would probably be in your early 20s and so it might take you a bit longer, but you’d get there in the end. Now, you might be 35 or 40 before you start trying, and you’ll have more of a problem getting your partner pregnant because your age just compounds the problem.
The terrible emotional toll
That will be of little comfort to couples such as Paul and Liz Lockwood. They married six years ago, when they were aged 26 and 25 respectively, and decided to try for a baby straight away because Liz has polycystic ovary syndrome.
After 18 months without success, they sought medical help – only to learn that Paul has a low sperm count (10-12 million a ml), probably as a result of an operation he’d had for an undescended testicle at the age of 11.
“Neither of us ever dreamed the cause of the problem would be me,” says Paul. “The doctors are surprised we’ve not been able to conceive yet, we’re young and have time on our hands, so we’re hopeful that we will get there.” – Daily Mail