When Zhang Feng wrote his first book in 1997, his wife locked the draft in a drawer out of fear that it would bring public shame on her husband.

Zhang Feng talks about sex in this file photo that shows his office in Guangzhou, capital of Guangdong province, packed with books on sexology, including those he wrote himself. Que Daohua / for China Daily

The book, The ABCs of Sexual Relationships, delved into sex, a taboo subject in China. It took Zhang more than eight months to convince his wife the book was part of his duty as director of the Guangdong Provincial Commission of Population and Family Planning.

"Talking about sex is my job," Zhang, 58, told China Daily during the recent three-day Guangzhou Sex Culture Festival.

Zhang became an overnight celebrity in 2003 when he launched the annual festival.

Zhang dubbed the event the "Under the Covers Project", saying the government should pay as much attention to the issue as it did toward the then-ongoing nationwide "Vegetable Basket Project", which addressed the public's need for food.

"Sex is like food. It functions at the very root of human society," said the soldier-turned government official, citing his decades-long experience in family planning.

In the following years, Zhang, the country's first high-ranking official to openly discuss the once-taboo topic, kept making a splash in the media and the public for his campaigns on sex.

He has launched a number of programs on safe sex, birth control, healthy pregnancy and maintaining a happy sex life between husband and wife.

He even expanded the topic to include a number of social issues, such as the sexual needs of migrant workers and the relationship between government corruption and sexual scandals.

As if that's not enough, he discusses these topics in the first person, using a cartoon image featuring his trademark big nose.

Zhang is now more widely known as fengge (Brother Feng), the nickname he adopted in his books, rather than his official title.

"I'm glad that people have come to take the issue of sex seriously and treat it with knowledge," Zhang said, referring to the more than 300,000 visitors who showed up on the first day of this year's sex culture festival.

Zhang remembered when the festival was launched in 2003.

"It caused such an uproar among the public," he said. "Now people take it as a routine happening. That's good."

A Guangzhou native, Zhang joined the army in Yunnan province after graduating from high school.

In the 1980s, he had the chance to choose between being a leader in an enterprise in Yunnan province or going back to Guangzhou to work in the local commission of population and family planning.

Despite a lack of relevant experience, Zhang chose the latter.

"Because my moving back to Guangzhou was very important to my family at the time," Zhang recalled.

"Moreover, I thought as long as I did my best, I could always excel in any field."

He has been true to his belief.

In the first few years, Zhang devoted all his spare time to the study of sexology. He collected and read any book on sexology he could find from across the country.

In 1990, when such books were still hard to find on the mainland, Zhang even traveled to Hong Kong and bought a few of them, which led to a fight with Customs officers.

"They said they had to confiscate the books because they were pornographic. I told them that I'd bought the books for work, but they didn't believe me," Zhang said with a joking smile. "They asked, 'Why would an adult man like you care about women's stuff?'"

Zhang said this was not the first time he had encountered such mockery about his job.

"I didn't blame them for their ignorance," he said. "I blamed myself for not being able to correct their misconceptions about sex."

Zhang said he became determined to take sex off the list of taboos soon after he joined the local commission of family planning, as he was shocked by the rampant sexual illiteracy among the public at that time.

He said he heard of a new couple in a small village in Guangdong province who killed each other on their wedding night because the husband doubted the wife's virginity.

"From events like that, I've come to understand sex plays an important role in many issues like the stability of marriage, families and social events," Zhang said. "To give you an example, 95 percent of officials' corruption scandals involve sex."

Zhang said he believes the more people talk about sex, the more rational people become about the issue.

"I've never considered it wrong for me to talk about sex. I once even handed two condoms to two deputy governors to remind them of the importance of the work of population and family planning, especially in a province like Guangdong, which has the country's biggest migrant population," Zhang said.

Zhang also lectures at universities. Due to his sense of humor, he has earned a reputation among college students.

But Zhang's eloquence still fails him at times.

Last November, when a series of 10 books were published featuring his cartoon image talking about sex, a local newspaper wrote a story with a headline that read: "Official teaches you how to make love."

"My mom, who is now in her 80s, was very angry when she read the story," Zhang recalled with a laugh. "It was not easy for me to finally calm her down."