A SYDNEY doctor who is a member of the Exclusive Brethren Christian sect has been banned from practising as a GP after he prescribed chemical castration to a young man who sought a ''cure'' for homosexuality.

Mark Christopher James Craddock, 75, wrote the 18-year-old patient a script for the anti-androgen therapy cyproterone acetate (Cyprostat) during a 10-minute consultation in his home in February 2008.

Chemical castration ... the drug Cyprostat was prescribed to cure a gay man's homosexuality. Credit:Michel O'Sullivan

The patient, who cannot be named for legal reasons, was at the time a member of the Exclusive Brethren church.

In a letter of complaint to the Health Care Complaints Commission, the patient said when, at the age of 18 he came out as gay, a church leader told him, ''there's medication you can go on''. ''He recommended that I speak to Dr Craddock on the matter with a view to my being placed on medication to help me with my 'problem','' the New Zealand resident said.