Many people who suffer from "sexual dysfunction" do not seek treatment for it or regard it as a serious problem.

A survey of GP patients found that 40 per cent of women and 22 per cent of men had been diagnosed with at least one sexual problem. But women reporting a "lack of desire" - which is included in sexual dysfunction - were much less likely to have consulted their doctor than those with other difficulties, such as failure to achieve orgasm.

The results, published in the British Medical Journal, come from a survey of 1,000 women and 450 men visiting GPs in north London."Many people do not regard lack or loss of desire as a serious difficulty," the study found.

When women who reported loss of desire were eliminated from the survey, the number of female patients with a sexual problem fell from 40 per cent to 27 per cent.

Pharmaceutical companies have been accused of creating the disorder of sexual dysfunction to profit from new drugs. Irwin Nazareth, who carried out the survey with colleagues from the Royal Free and University College Medical School, London, believes sexual dysfunction needs to be redefined.

The researchers said further evidence was needed to support medical treatments for a lack of desire. "For many people, reduced sexual interest or response may be a normal adaptation to stress or an unsatisfactory relationship."