BEIJING -- Sun Xiaofang, a math teacher working for a training school in Beijing, clearly remembers her middle school biology class.

Her teacher glossed over the basic anatomical and physiological differences between men and women in a textbook in less than 20 minutes, telling the students to "read it by yourselves after class".

"Girls flipped over those pages while blushing, and all the boys kept silent," Sun, 25, said. "The atmosphere in the classroom was so embarrassing, and hilarious."

The 20-minute lesson was the entire formal sex education she received, an all too familiar experience for young Chinese, with talking directly about sex often difficult for parents.

"It is too late for students to receive sex education after they enter adolescence," said Pan Suiming, director of the Institute of Sexuality and Gender at the Renmin University of China.

SEX WOES

Talking about sex remains a taboo in Chinese culture. Some experts consider the lack of proper sex education, particularly in schools, as one of the factors leading to serious health consequences in China, such as the growing numbers of HIV infections and staggeringly high abortion rates.

Zhang Yinjun, director of the AIDS Prevention Education Project for Chinese Youth, told Xinhua that Chinese adolescents now have the fastest-growing numbers of HIV infections. And over 90 percent of infections come through sexual transmission.

From January to September 2016, there were 96,000 new HIV infections, with 24.4 percent in the 20-29 age group, according to China's National Center for AIDS/STD Control and Prevention.

The core measure in promoting AIDS prevention for Chinese youth is to implement proper sex education, Zhang said.

Teenage pregnancies and premarital abortions are also rising. The National Health and Family Planning Commission reported in 2015 that approximately 13 million abortions are performed annually in China.

Today, an increasing number of Chinese adolescents are engaging in premarital sex, in many cases with only vague knowledge of safe sex.

"As the result of secretive sex education in China, most unmarried Chinese adolescents know little about the consequences of premarital sex," said Chinese sexologist Li Yinhe.

CHANGES ON THE HORIZON

China is making strides to break the sex education silence. The Ministry of Education issued a guideline on Monday suggesting higher education institutions set up public courses on health education to teach students about sex and reproductive health.

"Compared to older generations in China, teenagers and their parents have more access to sexual knowledge," said Li, also a fellow with the Institute of Sociology at the Chinese Academy of Social Sciences.

"Sex, Reproduction and Health of the Human" has been a popular selective course at Peking University for 20 years. It focuses on cultivating healthy altitudes toward sex and respect to life, and is well received by students.

"Sex education, as a required course in our life, concerns everyone's health and future, and it should be part of compulsory education," said professor Yao Jinxian, who teaches the course.

In recent years, there have been stronger voices calling for better sex education in China. Liu Wenli, a professor from Beijing Normal University, has been running a WeChat public account called "Love and Life" since 2014, offering a free subscription service on sex education information.

"Sex education is conducive to fostering young people's abilities in making resolutions, communicating and reducing risk in problems related to sex," Liu said.

By reading articles published on the account, subscribers can find answers to questions from "how to explain periods to your children" to "what if your kids touch their reproductive organs frequently?"

Liu and her team have also been popularizing their "Cherish Life" sex education textbooks for Chinese children. Each month, the team visits kindergartens and primary schools in Beijing to observe lessons and give instructions to teachers.

"Awareness of sexuality has been heightened to some extent, but it is still not enough," Liu said.

Sun Xiaofang is about to give birth soon, and she thinks about the future sex education of her child. "It will definitely be better than I had," she said.