A new report by the British Medical Association (BMA) says that gay and lesbian patients are often reluctant to reveal their sexuality to their doctors because they fear their treatment will suffer.
The report also claims that some homosexual doctors do not 'come out' to colleagues because they fear the consequences.
One gay doctor,Justin Varney, a public health doctor based in London, said the discrimination within the health service tends to be subtle, he was told he should not work in child health because of his sexuality.
The BMA has issued guidance on how the NHS should combat discrimination and Dr Vivienne Nathanson, the BMA's Head of Science and Ethics says everyone has the right to be treated equally, regardless of their sexual orientation.
The BMA report is published at the start of Gay Pride fortnight, and follows the recent publication of legislation which outlawed discrimination on the grounds of sexual orientation.
It calls for a series of measures including guidance on sexual orientation in NHS equal opportunities policies, and a crack-down on incidents of homophobia.
The BMA says simple changes would reduce feelings of discrimination.
By using gender neutral language when talking about a patient's partner, and not assuming sexual health, the primary health needs of gay patients would be met.
The report also includes guidelines for teaching medical students how to act in a non-judgemental way towards gay and lesbian colleagues and patients.
Dr Sam Everington, co-chair of the BMA's Equal Opportunities Committee and Deputy Chairman of the BMA, says future doctors have a responsibility to their colleagues and patients, and sexual orientation should be included in the medical school curriculum.
Dr Rachel Hogg, co-chair of the Gay and Lesbian Association of Doctors and Dentists (GLADD) says the NHS estimates that at least 1 in 20 of the population are lesbian or gay therefore an increased awareness that colleagues and patients may not be heterosexual is crucial to treating each other sensitively and respectfully.