Chemicals linked to low sperm counts

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The Independent Online
STEVE CONNOR

Science Correspondent

The Government yesterday accepted there may be a link between chemicals in the environment and falling sperm counts in men, but rejected calls for additional controls on the chemical industry.

An investigation by scientific advisers to the Government confirmed the overwhelming evidence for a rise in serious disorders of the male reproductive system, as well as an increase in breast cancer among women. Their report, however, stressed there was insufficient research to pin the blame on any single group of synthetic chemicals.

The Department of Environment said sufficient controls were already in place to limit releases of chemicals into the environment and the food chain. ''The report provides no justification for any immediate additional action on any particular chemicals,'' it said.

Professor Lewis Smith, director of the Institute for Environment and Health at Leicester University, led the inquiry into research indicating a significant fall in sperm count and sperm quality over the past 50 years and a corresponding rise in male reproductive problems, such as testicular cancer and genital abnormalities.

He said the ''balance of evidence'' showed that sperm count and quality was falling, testicular cancer rising and that there was a ''correlation'' between the two. However, although there was a lot of research indicating chemicals in the environment might be responsible, ''we were unable to find evidence of a causal link'', he said.

Scientific data from around the world suggests that cases of testicular cancer over the past two decades have increased by one-third; that sperm counts have fallen by about 2 per cent a year over the past 20 or 30 years; that sperm quality - the number of mobile sperm - has fallen by about 1 per cent each year and that breast cancer in women has risen by about 25 per cent since the 1940s.

Research on laboratory animals and observations on wildlife has produced convincing evidence that certain chemicals, both synthetic and natural, can mimic female hormones, to produce an ''oestrogenic'' effect that inhibits the normal development of the male reproductive system.

The Institute for Environment and Health identifies certain chemicals of ''concern''. They include organochlorine pesticides, such as DDT, polychlorinated biphenyls, which are highly persistent in the environment, and non-ionic surfactants used extensively in detergents, household chemicals and the textile industry.

But Professor Smith rejected calls from environmental groups Friends of the Earth and Greenpeace to ban certain chemicals suspected of being involved. ''It would be a dangerous move because if you have guessed badly you have left behind the chemicals in the environment doing the damage,'' he said.

Although laboratory research has shown certain chemicals to cause reproductive problems in animals, the doses were far higher than those to which humans were exposed, he said.

Professor Smith said that although he was working on the principle that sperm counts and sperm quality was falling, there was as yet no proof that this was having a significant affect on male fertility. ''There is no convincing evidence of a general fall off in fertility.''

Reports of a rise in male infertility could be due to an increase in the number of men who now report problems with their fertility compared to a generation or two ago, he said.

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