A Christian teaching body has written to the education secretary urging the government not to go ahead with its proposed ban on conversion therapy.
The letter from the Association of Christian Teachers (ACT) to Nadhim Zahawi warns that children and teaching professionals "could be harmed by the proposals".
It says that children with gender dysphoria may not be able to access support, while teachers will be left at risk of criminal convictions or being barred from working with children if they do not affirm a child's desire to change gender.
"The definition of what can be described as 'conversion therapy' is expansive, and could even include pastoral conversations, resulting in unsatisfactory outcomes for children and schools," the letter reads.
It continues, "The proposals will harm children who may need to talk about this sensitive and personal area of gender/sexuality with a school professional, especially those who want to remain in the sex category assigned to them at birth, despite feelings of dysphoria.
"Allegations leading to criminal convictions and a bar from working with children, could result for any adult who does not affirm a child into a trajectory towards changing sex/gender.
"This would inevitably mean that children will remain dangerously unsupported due to teachers/professionals being wary of criminal prosecution."
The government is holding a public consultation on the proposals until 4 February.
In the letter, ACT Executive Officer Elizabeth Harewood says that a conversion therapy ban could infringe on the human rights and liberties of children by preventing them from being able to voluntarily request pastoral counselling or prayer.
The organisation said that Christian teachers should be free to "gently and graciously" express their religious beliefs on sexuality and gender when prompted by children.
It also said that the government "has a duty to protect children" from "progressive and aggressive political ideologies", and that "nuanced discussions" aimed at helping children to explore issues of gender and sexuality, as well as feelings of "distress" around these issues, "should not be classified as conversion therapy, despite the insistence of lobbying groups".
"To view the complexity around supporting a child experiencing gender distress as either 'affirm' or 'convert' is over simplistic and deeply damaging," ACT said.
"Professionals should be free to explore these issues with children without fear of acting illegally."
These concerns have been echoed by Christian Concern, which has also written to the education secretary.
Steve Beegoo, Head of Education at Christian Concern said the potential criminalisation of teachers and pastoral staff in schools for having conversations with young people "will prevent vital support being given to vulnerable children".
"In seeking to 'close loopholes', activists would have succeeded in creating, by law, a situation where harm and unhealthy and unlawful behaviour would increase in our nation's children through the decrease of counsel from adult professionals," he said.
Andrea Williams, chief executive of Christian Concern, warned of "silence and self-censorship" if the law is passed.
She urged the government to listen to the outcry from educators, parents and church leaders.
"At Christian Concern, we regularly encounter families, schools' workers, and children, who could be harmed by the current proposals," she said.
"As the definition of conversion therapy currently stands, it will result in many highly disturbing outcomes for children and in schools. Some children and young people who want to remain in their biological sex category, despite their feelings, will remain dangerously unsupported. Professionals and teachers will be reluctant to speak to children on the issue due to fear of 'criminal' allegations being brought against them. They will be forced into silence and self-censorship and will feel unable to help or advise a child who they believe is vulnerable.
"We believe that the proposed ban should be withdrawn, and that the department should support its withdrawal, and we have requested an urgent meeting with the education secretary."
