Many LGBT people in China are being forced to undergo "conversion therapy", often done by unscrupulous, unlicensed providers in a sector that operates with little oversight by the authorities, rights groups said.
Though widely discredited by doctors, conversion therapy is an attempt to change a person's sexual orientation through various means such as hypnosis, drugs, acupuncture and even electric shock therapy.
In China, the therapy is often offered by centres not licensed to practise medicine, as well as by public hospitals, in the absence of an outright ban.
"It's not just a commercial scam, but an action that violates people's rights," said Wang Zhenyu, head of the Public Interest Law Center on Equal Rights for LGBTI, one of the groups that compiled the report.
The National Health Commission did not immediately respond to a request for comment.
Chinese authorities removed homosexuality from its list of diseases in the Chinese Classification of Mental Disorders, a national clinical guide, in 2001.
But many gay people still face pressure from their families to undergo the treatment.
In 2016, a man surnamed Wang, sued a hospital where he had been locked up for 19 days while receiving therapy in the city of Zhumadian, the groups said in their report, released late on Wednesday.
The man said his family had forced him to get the therapy
In another case in July, a young transgender woman's family committed her to a hospital against her will in the southern city of Jingdezhen, the groups said.
A programme manager at the other group involved in writing the report, Beijing Gender, said some centres illegally used electric shock therapy in their therapy.
An activist named Peng Yanzi went undercover in a conversion therapy centre in 2014 and was forced to undergo electrotherapy. He then brought the case to court and won.
There are at least 96 centres and hospitals across China that offer the therapy, the groups said in their report.
They questioned health departments in 25 cities with such centres to see if any had taken action against them and found no evidence of any in 17 of them.
Four cities had punished medical institutions between 2017 and 2018 for practising psychiatry without proper credentials, among them the capital, Beijing and the southern city of Changsha in Hunan, the groups said.