The medical treatment being offered to children and young people with gender dysphoria is the next "medical scandal", JK Rowling has said.
The Harry Potter author has continued to challenge the prevailing transgender ideology despite a backlash against her views.
Over the weekend, she linked to an academic article on Twitter that was exploring the terminology around transgenderism.
The article calls the "push" for early bodily modification and hormones by some transgender patients "a cause for concern".
It argues that doctors and psychiatrists should be free to explore different routes with gender dysphoric patients but the space for this is being increasingly shut down because many are concerned they will be accused of transphobia.
"Psychiatry sits on this knife-edge: running the risk of being accused of transphobia or, alternatively, remaining silent throughout this uncontrolled experiment," the paper says.
"Respectful debate, careful research and measurement of outcomes are always required."
Commenting on the article, Rowling said she had received thousands of emails on gender identity theory, amounting to more than she has received on any other subject.
Many of the emails came from professionals in the fields of education, medicine and social work, she said.
"All are concerned about the effects on vulnerable young people," she wrote in a Twitter thread.
"It feels as though we're on the brink of a medical scandal," she said.
She said the "bleak truth is that if and when the scandal does erupt, nobody currently cheering this movement on will be able to credibly claim 'we couldn't have known'," she said.
Last month, Rowling wrote in a personal essay that she was concerned about the impact of transgender ideology on single-sex spaces. She has frequently spoken out on the issue on Twitter, even while being criticised by others, including the stars of the Harry Potter and Fantastic Beasts movies, Daniel Radcliffe, Emma Watson, Rupert Grint and Eddie Redmayne.
Equalities minister Liz Truss has recently said that the UK Government would be putting restrictions in place on the "irreversible" medical treatment for young people with gender dysphoria.