China isn't known for being progressive with sex education, but a new textbook is changing that.

The textbook has been introduced to several Chinese elementary schools, and is going viral for its frank discussion of sex and homosexuality -- a taboo topic in Chinese society.

Many who are in support of the book are praising it for teaching children how to recognise situations of sexual abuse.

Even more people are surprised that the book portrays same-sex relationships in a positive light, and talks about topics like rights for same-sex couples.

But voices against the book say elementary schoolers are way too young to grasp these concepts -- and certainly to be exposed to graphic illustrations of intercourse and genitalia.

In a now-deleted Weibo post, a mother from Hangzhou said she found her child reading the book, and was shocked at the contents.

"Do you learn this in second grade now? Has this book really been put together properly? I can't even read the last bit. Is this a fake book from the school?"

The mother said she was perturbed that the school didn't inform the parents that the textbooks would be handed out.

"We only found out about this book when our child was reading 'Daddy's penis is inserted into Mummy's vagina'," she said.

"If you were a parent and heard this without any warning, wouldn't you be shocked?"

Other netizens said the subject needed to be handled more delicately.

"I feel that it will only prompt children to explore what they don't understand at a young age, like pornographic websites," said SouthXiaoMing. "You can teach children how to protect themselves, but you shouldn't use nudity and graphic images to stimulate their curiosity, especially when they are still undergoing puberty."

"Incredibly progressive"

But those in favour of the book say it's leapfrogged the traditionally conservative manner in which sex and gender is discussed.

This group includes the state-run Global Times, which published an op-ed supporting the textbook, and slammed naysayers for sensationalising and distorting its contents.

"A book that was meant to let young children learn more about gender and sex, and protect themselves from sex predators has been distorted and turned into pornographic depictions by the media and corporate Weibo accounts," the piece said.

"The syllabus is incredibly progressive, and is better than similar texts from other developed countries."

Another Weibo user, 369RibsLaLaLaAhChai added: "I saw that line which said that 'gay people and heterosexual people had the same rights; don't discriminate' and I nearly cried."

Beijing Normal University, which created the textbook, explained in a statement that the book had gone through nine years of testing in an elementary school attached to the tertiary institute, and is currently being rolled out in 18 elementary schools in China's capital.

"The book was rigorously designed, tested, and revised. In China, sex has been a taboo issue; parents still do not want to discuss these things with their children, while children are increasingly exposed to inaccurate sexual portrayals in the media; we hope children can form their own values based on accurate, scientific information."

According to a survey published in 2016, 44 percent of Chinese university students say they hadn't gone through sex education before.

Chinese millennials are displaying increasing willingness to talk about sex and civil rights. Last year, a gay couple took the civil affairs bureau to court, after they were denied the right to marry in the communist country.

（作者：产品中心）