Gender-bending chemicals are to be exempted from tough new Europe-wide safety controls despite increasing concern that they are causing bizarre sex changes in children and wildlife, leaked documents reveal.

Confidential proposals show that the chemicals will be treated much less strictly than other dangerous substances in a European Commission directive to be finalised in coming months. Many are likely to escape control altogether.

The proposals - drawn up by the British Government as part of its EC presidency - will create a storm of protest, not least because they fly in the face of a formal warning given by more than 125 of the leading scientists in the field three months ago.

The scientists, who had carried out research on the chemicals for the EU, said they were "concerned about the high level of male reproductive disorders" in European countries and called for urgent action.

Sperm levels have been dropping across the industrialised world, and the chemicals - found in toys, plastics, cosmetics, pesticides, flame retardants and many other common products - are thought to be responsible.

Research published in May showed that boys born to mothers exposed to phthalates, used to make plastics more pliable, had smaller penises and other signs of genital feminisation.

Three years ago, a Dutch study showed that boys exposed to other gender-bending chemicals in the womb grew up preferring to play with dolls and tea sets.

Research has demonstrated that half of all the fish in British lowland rivers are changing sex because of pollution.

The EC planned to ensure, under the directive, that suspected gender-bending chemicals - along with substances thought to cause cancer and birth defects - went through a special safety screening before being used, but this ran into opposition from the chemical industry.

A new version of the directive - put forward by Britain for approval by EU governments - exempts the chemicals from the checks unless there is "scientific evidence of serious effects to humans or the environment".

Scientists say that this provision, which does not apply to the chemicals suspected of causing cancer and birth defects, means that the gender-bending chemicals could only be brought under control after they had actually done serious damage to people and wildlife, making a mockery of the object of the legislation.

Dr Andreas Kortenkamp, of the University of London's Centre for Toxicology, said that "very few, if any" of the chemicals causing concern would be controlled under this provision.

Dr Gwynne Lyons, toxics policy officer at World Wildlife Fund UK, said: "The Government well knows that these proposals will mean that important gender-bending chemicals will not be subjected to the tough controls urged by scientists. But it only seems to be listening to industry."