Ann Widdecombe has been criticised for promoting the idea that gay people can be made straight.
Writing in her Daily Express column on Wednesday, the former senior Conservative MP said: "Anybody can get help for anything from psychotherapists in this country except apparently gays who do not want to be gay".
Widdecombe was defending Lesley Pilkington, a counselor who has been found guilty of professional misconduct by the British Association for Counselling and Psychotherapy (BACP) after she agreed to help try and convert a gay patient to heterosexuality.
The patient was in fact an undercover reporter.
"A man who wants to be a woman will receive not only the necessary operations but also a huge amount of psychological support and counselling," Widdecombe said.
"Yet the unhappy homosexual should, according to gay activists, be denied any chance whatever to investigate any possibility of seeing if he can be helped to become heterosexual."
Ben Summerskill, the chief executive of gay rights campaign group Stonewall, said people would be "deeply distressed" by Widdecombe's defence of the "murky world of so-called conversion therapy".
"This voodoo theology hurts people who’ve been bullied into believing that they should be ashamed of being gay. It’s founded on pure prejudice, so it seems an odd way for Miss Widdecombe to promote Christianity’s message of love and respect for all," he said.
Widdecombe, a committed Christian, stepped down from parliament in 2010 having failed in her bid to become Speaker of the House of Commons.
She converted to Catholicism in 1993, leaving the Church of England following the ordination of women. In 2009, Widdecombe debated Stephen Fry and the late Christopher Hitchens on whether the Catholic Church is a force for good in the world.
Watch the debate: