Christians fear it will lead to evangelical pastors and churches being criminalised for ordinary church activities like prayer and pastoral counselling.

Dr Elizabeth Woning, pastor at Bethel Church in Redding, California, spoke about her work for the Changed Movement, a community of Christians who have left the LGBT lifestyle behind.

"This is a population that most people believe doesn't exist," she said.

"Anyone who's benefitted from prayer ministries and programmes that specifically address unwanted same-sex sexual behaviours have been maybe intentionally or unintentionally excluded from the majority of the studies that are being used to substantiate the harms of so-called change-allowing therapy or conversion therapy."

Dr Woning was a lesbian and former activist for LGBT ordination before being healed by a radical encounter with Jesus and marrying her husband in 2005.

She said that the lived experience of ex-gay people was "vitally important" to the current debate, and that therapy bans risked "great harm" to people looking for a way out.

"Therapy bans threaten the lives of individuals like us, whether minors or adults, who are in pain over their LGBTQ feelings," she said.

"Bans cause harm because they don't ever allow you to address the pain. They disallow personalised exploration with a professional to address the factors that could be formitive in the development of same-sex sexual behaviour.

"LGBTQ-identifying people must have the right to follow their faith wholeheartedly and pursue their own life goals, even when it means moving away from LGBTQ or gender confusion, and identifying as heterosexual."

She said it was important that pastors and therapists be allowed to create safe spaces and opportunities for people to explore the pain of their unwanted sexual attractions or identities.

"For most of us at Changed, our religious convictions fundamentally guide our worldview and sense of personal identity. It's important that legislators grasp the gravity of forcing a person with unwanted same-sex attraction, no matter their age, to disavow their religious faith to embrace LGBTQ identity or same-sex feeling or behaviour," she said.

Dr Woning also questioned why under-18s should not be allowed to receive such help.

"In an era when gender identity has such high stakes, pointing to life-altering drugs and surgeries that frequently cause sterilisation, shouldn't children be given every opportunity for self-discovery and relief from trauma that might alleviate gender dysphoria," she said.

She added: "People like us want answers ... saying 'I was born this way' just doesn't cut it."

The symposium was co-organised by Christian Concern, which has warned of the dangers of a conversion therapy ban not only to pastors but also parents wanting to raise their children within a traditional sexual ethic.

Christian Concern CEO Andrea Williams expressed concern at the impact on free speech.

"A whole load of people will just go silent," she said. "When there's an Act that comes in and subdues free discourse and how people interact pastorally and professionally, there will be a chilling effect.

"It's a very easy way of targeting those who seek to do good."

Dr Laura Haynes, a psychologist and experienced therapist, said the proposed ban and the research supporting it was being driven by ideology and that the end result would be "unpractical and unsafe".

"Everyone should have the right to walk away from sexual or gender practices and experiences that don't work for them and have support to do so without government approval for their reason and without discrimination," she said.

"The government proposal forbids minors the right to help to live according to their religion. It is a serious attack on the human rights of minors to freedoms of speech, religion and belief.

"There are rational reasons why people want and freely choose change-exploring therapy."

Registered physician Dr Andre Van Mol warned that minors were simply too young to fully grasp the implications of losing their fertility or full sexual function forever.

"Banning counselling choice condemns already at-risk sexual minority youth to experimental and unproven hormonal and surgical gender affirming therapy (GAT)," he said.

"GAT permanently and prematurely medicalises minors for a condition that overwhelmingly resolves by adulthood.

"Why do that? It is not proven to be effective or safe, it does not reduce suicides, and is not the standard of care for gender dysphoric minors."

He continued, "Minors cannot give truly informed consent for a life of sterility and compromised sexual function. They have developing brains, their minds change often, and they don't grasp long-term consequences.

"Gender Affirming Therapy's suicide reduction claim is a myth, used as emotional blackmail against parents and the public.

"The chemical castration and surgical mutilation of otherwise healthy young bodies is not health care."

IFTCC Chairman, Dr Mike Davidson, agreed, saying: "There is no reason to believe that talking therapies for sexual orientation cause harm, yet there is a mountain of evidence that transgender affirmation, puberty blockers, cross-sex hormones and surgery cause significant damage to adults and children.

"How can the government possibly justify a ban on conversion therapy while paying for these damaging transgender treatments?"