I have had a bodybuilder asking me if he stops using these steroids when will his genitals return to their normal size?

Dr Jane Milson, Grimbsy GP

Grimsby GP Dr Jane Milson told the conference that sportspeople were under increasing pressure to perform well and therefore were increasingly tempted to take performance enhancing drugs.

She said: "I feel sportsmen and women are insufficiently aware of the risks they are taking.

"I have had a bodybuilder asking me if he stops using these steroids when will his genitals return to their normal size? I was very sad to advise him that perhaps they won't."

Dr Milton also told the conference: "I was shocked recently to discover that bodybuilders are using the needle exchange scheme originally set up for the benefit of heroin users."

She said one pharmacist running a scheme regularly saw 25 bodybuilders who came to him for clean needles.

The possible side effects of anabolic steroids include:

• Acne
• Premature baldness
• Increased aggression
• Impotence
• Sterility

Dr Milton also highlighted the risks associated with erythopoetin, a substance allegedly used by cyclists in the Tour De France last year.

She said it increased the risk of blood clots, stroke, heart attack and sudden death.

Another performance enhancing drug, human growth factor, had been linked to the brain disorder CJD, she said.

Dr Evan Lloyd, chairman of the British Association of Sport and Exercise Medicine, said the GMC had the power to strike off unscrupulous doctors who collude with sportspeople to improve performance.

But he also warned that some doctors, in prescribing performance enhancing drugs, were trying to wean people off them slowly in the same way that doctors prescribe methadone for heroin addicts.

Anabolic steroids have a number of legitimate medical uses, such as treating muscle wastage in patients in intensive care.

The BMA voted to examine the issue and to draw up an official policy.