( BBC ) - Doctors' leaders have called for stricter rules on when medics can "conscientiously object" to procedures.
The British Medical Association heavily criticised draft GMC guidance that would allow doctors to opt out of any procedure for ethical reasons.
The plans would give doctors "a licence to discriminate" and should be strictly limited to certain procedures such as abortion, the BMA warned.
But such precise restrictions would not work in practice, the GMC said.
It is currently widely accepted that doctors can "conscientiously object" to certain procedures associated with life and death issues, such as withdrawing life-prolonging treatment, the BMA said.
However, the only absolute right to objection under law is for carrying out an abortion.
The new draft recommendations from the GMC, which have been under consultation, say doctors can object to any procedure for which they have a moral, cultural or religious disagreement.
The BMA said it was "extremely concerned" about how far these objections could extend.
For example, could doctors refuse to refer a lesbian couple for fertility treatment, refuse to carry out a sexual health test on a homosexual or object to treating a Jehovah's Witness who has refused a blood transfusion?
Conscientious objection should be limited to a shortlist of clearly defined procedures, the BMA said.