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Concerns over decreasing male fertility rates

10 March 2008
Appeared in BioNews 448

Two new studies have identified factors that could be causing a decline in male fertility. Research published in the journal Fertility and Sterility on the anti-impotence drug Viagra concluded that men taking the drug could be damaging their sperm and lowering their ability to conceive. Another study, published in the environmental journal the Ends Report, suggests that pollution from chemicals such as dioxin can lower a man's sperm count.

The first study, led by Dr David Glenn at Queen's University Belfast, , treated sperm in vitro with Viagra, and found treated sperm to be more active than untreated sperm, but also that the 'acrosome', which produces enzymes that help the sperm penetrate the egg, was damaged by the drug. Tests in mice showed that sperm treated with Viagra produced 40 per cent less embryos than untreated. Dr Glenn is concerned that the drug is being prescribed to couples seeking help for fertility problems, and says that 'giving male partners something that could make the problem worse is scarcely the right approach'. He has also raised issues with younger males using the drug recreationally, who may be harming their chances of starting a family in the future.

The second study identified another factor thought to influence male fertility rates: pollution from chemicals such as dioxin, released through industrial processes and found in the atmosphere. A chemical explosion in Italy in 1976 exposed people to a cloud of highly toxic dioxin. A study 22 years later of male volunteers who were exposed found that men who were aged under nine at the time of the explosion had 43 per cent lower sperm counts than a control group. Men who were aged between ten and 17 when exposed, however, had sperm counts 62 per cent higher, and men who were over 17 were unaffected. The findings suggest that dioxin is a potential factor responsible for falling sperm counts, and also puts a question mark over other industrial chemicals.

Endocrine-disrupting chemicals are also thought to be affecting fertility rates. Three such chemicals have been investigated by scientists at the National Food Institute, Technical University of Denmark. When the chemicals were administered separately, they were harmless. Concurrent exposure, however, resulted in malformed sexual organs in the fetuses, showing potential cocktail effects of chemicals should be taken into account when investigating their effects on fertility rates. In Denmark, just under five per cent of boys are born with a certain malformation of their sexual organs.

Meanwhile, new hope was given to infertile couples in Australia, where Menevit, the 'first ever drug to for male infertility', has been developed. It contains antioxidants and works by acting on free radicals that fragment sperm, the main cause of infertility. In a preliminary study of 60 infertile men, the rate of pregnancy was increased significantly, but larger clinical trials are required before the drug can be merited.

Dioxin pollution 'caused drop in sperm count'
The Daily Telegraph |  25 February 2008
Male Fertility May Be Harmed By Mix Of Endocrine Disrupters
ScienceDaily |  26 February 2008
New hope for men battling infertility
TVNZ |  6 March 2008
Viagra could harm sperm and reduce fertility, say researchers
The Daily Mail |  24 February 2008
Viagra could hinder baby chances: study
The Age |  25 February 2008
Viagra may harm men's fertility, report warns
The Daily Telegraph |  26 February 2008
7 January 2013 - by Dr Charlotte Warren-Gash 
Global rates of infertility have remained relatively stable between 1990 and 2010, according to a study that compiled data from 277 national surveys in 190 countries....
10 December 2012 - by James Brooks 
Between 1989 and 2005, the sperm count of French men dropped by a third, according to research...
13 June 2011 - by Kyrillos Georgiadis 
A new fertility test for men which can detect DNA damage in sperm has been developed in the UK. The test, called SpermComet, could save couples undergoing fertility treatment both time and money, since it will allow clinics to fast-track patients to the most appropriate treatment, say its developers...
1 November 2009 - by Dr Jay Stone 
Exposure to a combination of excessive stress and everyday chemicals whilst in the womb can have implications for future male fertility, according to Dr Amanda Drake and colleagues from the Centre for Cardiovascular Science and Reproductive Biology at the Queen's Medical Research Institute, University of Edinburgh....
18 February 2008 - by Dr Charlotte Maden 
A report printed in the British Medical Journal this week about the trends in fecundity over time has called for more studies into the environmental factors contributing to reduced fertility rates. Infertility is a common problem in affluent societies, affecting around 15 per cent of couples trying...
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