"Mama!" Gu Mengran, 12, turned to her mother when asked about the sex education class at school, giving a shy smile.

Encouraged by her open-minded mother, Gu finally opened up.

"Our teacher always turned over that page and told us to read it by ourselves," she said. It is now her first year in the junior high section of the Nanjing Foreign Language School in the eastern Jiangsu Province.

It seems this is the standard way for teachers across China to deal with the sexual health part of their public health classes.

Wang Shengjie, a 26-year-old Chinese teacher at the Beijing No. 80 High School, recalled how teachers at her middle school skillfully skipped the chapter.

In a culture where open talk about sex has been taboo for centuries, such reticence might once have been acceptable, but no longer.

The numbers tell the story.

At last year's sex culture festival in Guangzhou, capital of the southern Guangdong Province, birth control officials said about 17.7 percent of the province's high school students had had sexual experience.

The situation was different in past years, but not much. Well-known sexology professor Pan Suiming at the Renmin University of China in Beijing found in his 2001 survey that about 17 percent of the college students in China were sexually experienced.

Pan also found that about 6.5 percent of college students had tried sex during their high school years.

Given those circumstances, changes to the traditional methods of sex education seem imperative.

On December 26, the Ministry of Education issued new guidelines that said primary schools across China should teach pupils about the human body, including secondary sexual characteristics.

Previously, this sort of information was for high school students only, and teachers would pass over those pages in the textbook and leave them to read on their own.

The new guidelines stipulate that junior high school students should start learning about AIDS and how to prevent it.

Beijing anti-AIDS campaigner Xiao Dong applauded the new policy. "With the new policy, children can learn about sexual health at an earlier age. That's very helpful to their growth."

AIDS has been a driving force behind recent changes in sex education.

Ministry of Health figures show China has about 264,000 confirmed HIV cases and about 78,000 of them are AIDS patients.

Among those who contracted the virus in the first nine months of last year, about 40.4 percent were infected by heterosexual contact. Another 5.1 percent contracted the virus via male homosexual activity, a sharp increase over the previous years.

Xiao Dong, who heads the Chaoyang Chinese AIDS Volunteer Group, said his group was turned away by several universities when it proposed to hand out free condoms and set up condom-vending machines on campus.

"The way school managers avoid talking about sex as if it was a fatal disease will sow danger for the health of our younger generation," Xiao said.

Zhou Ping, a 27-year-old engineer who works for a U.S. company in Shanghai, said he and his friends in college learned the most about sex by watching pornography.

Zhou joked how he had a heated discussion with a friend in junior high school and concluded that babies are born after their parents walked hand in hand.

"Free and open discussions about sex can lead teenagers to the right growth path, especially the boys," he said.

Teacher Wang Shengjie, however, took a conservative view of the policy change. "Kids may be horrified if they know all the secrets of the human body at the age of nine or ten.

"But sex education at an earlier age is absolutely necessary," said Wang, especially for teaching children to beware of sexual predators.

Xiao also voiced concern. "Just like the teachers in the past, the key to this new policy is whether it can be effectively implemented."

According to the director of the teaching office at the Zhongguancun No. 1 Primary School in Beijing, the school will adjust to the new policy.

"We will assign teachers who have studied psychology in college to teach public health courses, which include sexual health," said the man, surnamed Deng.

Gu, although shy at first, said she wouldn't be embarrassed if she had to learn about AIDS or sex in class.

"Actually, one of my male classmates was curious about that page and chased our teacher after class for further explanation," Gu said, giggling.

Editor: Yan