Children in Yangpu district, Shanghai have sex education in August 2013. Photo: CFP

Most children remember their school days fondly, but for students of a school in Youxian county, in Central China's Hunan Province, it is a time they would prefer to forget.

A teacher from the county is awaiting trial over charges of sexual assault and sexual battery after 23 girls said that they were abused by the man over a period of three years.

School and education officials were aware of the abuse but no one informed the police, the Xinhua News Agency reporters discovered.

Moreover, the abuser appears to have targeted particularly vulnerable victims, as 18 of the 23 girls were "left-behind" children, those whose parents are migrant workers in other cities.

"We were ashamed to tell our grandparents. Every time my mother called, she would tell me to study hard and listen to my teachers. I could not bring myself to tell her what was happening over the phone," one of the victims said.

More than 60 million children are considered left-behind in China, and they are at greater risk of falling victim to abuse, lawyers and children rights campaigners agree.

Unfortunately, saving face and reputation often trump a desire for justice, especially for older care-givers, said Li Huiye, a lawyer at Tiandiren Law Firm in Hunan.

"Silence and private settlement is the preferred solution, instead of conviction," said Li, adding that such a culture enables sexual predators to commit crimes against children.

From 2013 to 2015, at least 968 incidents of sexual assault against minors, involving 1,790 victims, were reported in Chinese media, according to the sexual violence prevention center Girls' Protection Foundation.

Boundaries, education

Sex education can help prevent sexual abuse. Children are not being taught about their bodies, their right to privacy or how to define boundaries. This lack of understanding only exacerbates the stigma attached to victims of abuse, experts have said.

Fei Yunxia volunteers for Girls' Protection, and it is her responsibility to visit schools and teach children about their bodies and rights. During presentations the mood is often the same: students avoid eye contact and an awkward silence hangs in the hall.

During a recent presentation, she spoke to the students about their bodies and personal boundaries, as children that understand their bodies are more likely to know if certain interactions are appropriate or not.

Girls' Protection, which was founded in 2013, funds lectures, campaigns and research to prevent sexual violence against children.

"Before me, nobody told these students about their bodies, sex or how to protect themselves," said Fei.

In the last year, Fei has given lectures to 2,000 students in four schools in Hunan, and she wants to reach out to more.

"It is just hard to get support from schools or education authorities. They think the topic is 'sensitive' or 'unspeakable,' she said.

There is no sex-ed program on the prevention of abuse, and many schools would not even consider the subject, said Sun Xuemei, one of the founders of Girls' Protection.

No one to talk to

Xiao Yun is a survivor-turned-campaigner with Girls' Protection. She was sexually abused by her neighbor when she was 8 years old.

"There is hardly anyone for victims to turn to. The security net around children is far too porous," she said.

"After a lecture at a school, I received a text message from a girl who said she had a sexual experience against her will, but when I called her back, her phone was dead," she said.

According to the People's Public Security University of China, for every report of sexual abuse there may be at least seven unreported incidents.

Many believe that the compensation awarded to underage victims of sexual abuse does not reflect the severity of the crime.

A kindergarten student in Northeast China's Jilin Province was awarded just 1,000 yuan ($151) in damages after the court threw out the psychological damage claims filed by the victim's family. The child's abuser was the husband of the owner of the kindergarten.