Kemikalier suddar ut könsgränserna

They warned that while exposure to a single chemical may cause no harm, the cumulative effect could be profound.

Professor Sharpe's report was commissioned by the CHEM Trust, a charity which works to protect humans and wildlife from harmful chemicals.

There is evidence that male reproductive health is deteriorating, with malformations of the penis becoming more common, rates of testicular cancer rising, and sperm counts falling.

It is thought that all these conditions - collectively called Testicular Dysgenesis Syndrome (TDS) - are linked to disruption of the male sex hormone testosterone.

Professor Sharpe concludes that exposure to a cocktail of hormone-disrupting chemicals in the environment is likely to be at least partly to blame by blocking the action of testosterone in the womb.

His latest report highlights animal studies showing that testosterone-disrupting chemicals can cause TDS-like disorders.

In addition, de-masculinisation effects due to chemical pollutants in the environment has been reported in many species of wildlife.

The direct evidence of an effect in humans is so far less compelling - but is beginning to mount.

Minimise exposure

Professor Sharpe said: "Because it is the summation of effect of hormone-disrupting chemicals that is critical, and the number of such chemicals that humans are exposed to is considerable, this provides the strongest possible incentive to minimise human exposure to all relevant hormone disruptors, especially women planning pregnancy, as it is obvious that the higher the exposure the greater the risk."

New EU chemicals legislation, called REACH (Registration, evaluation, authorisation and restriction of chemicals) puts the onus on the chemical industry to prove that its products are safe.

Campaigners say it could be used to reduce exposure to hormone disrupting chemicals.

Elizabeth Salter Green, CHEM Trust director, said; "Chemicals that have been shown to act together to affect male reproductive health should have their risks assessed together.

"Currently that is not the case, and unfortunately chemicals are looked at on an individual basis.

"Therefore, government assurances that exposures are too low to have any effect just do not hold water because regulators do not take into account the additive actions of hormone disrupting chemicals.

"It is high time that public health policy is based on good science and that regulatory authorities have health protection, rather than industry protection, uppermost in mind."

Ms Green advised pregnant women to keep cosmetic use to a minimum and avoid DIY.

A government spokesperson said the report would be studied with interest, and that the risks to health of hormone-disrupting chemicals were regularly reviewed by the Scientific Committee on the Toxicity of Chemicals in Food, Consumer Products and the Environment (COT).

"The Food Standards Agency and the Health Protection Agency are also currently involved in work relevant to this issue. We will continue to consider any new evidence that emerges."

A statement from the COT in 2006 concluded there was no clear link between data from animal experiments and trends in humans - but it was an important area for research.