Zhang and her young contemporaries - though far from uniform in their views - are much more open in their attitudes to sex than their conservative parents and increasingly aware of the need for protection against sexually-transmitted diseases.

This sex savvy generation is set to spur sharp growth of the country's condom market, a key driver behind a deal by Chinese investors to buy the world's no. 2 condom business for $600 million (£466.42 million) from Australia's Ansell Ltd (>> Ansell Limited).

"Attitudes are certainly changing. We're increasingly open," said Zhang, adding her friends mostly chose brands like Reckitt Benckiser Group Plc's (>> Reckitt Benckiser Group Plc) Durex and Japan's top-selling brand Okamoto (>> OKAMOTO INDUSTRIES, INC.) due to their reputation for high quality as well as their visible marketing campaigns.

"This is a very important product, if it goes wrong just once then the consequence is severe," she said.

In China's big cities, condoms are now available in plain view: convenience stores on urban high streets often have condoms on display by the till, while brands like Durex have millions of followers on their China social media platforms.

On supermarket shelves Ansell's brands Jissbon - named to sounds like James Bond - and the higher-end SKYN brand sit alongside an array of local offerings with names like "Endless", "Pleasure More", "Double Butterfly" and "Donless".

Durex is by some distance the best-selling condom brand on Chinese online shopping platform Taobao, followed by Jissbon, Okamoto and local brands SixSex and MingLiu, according to data from Daxue Consulting.

Ansell said on Thursday it had reached an all-cash deal with China's Humanwell Healthcare Group Co Ltd (>> Humanwell Healthcare Group Co Ltd) and CITIC Capital China Partners for its condoms business. Humanwell declined to comment on its strategy for the Chinese and other markets. CITIC couldn't be immediately reached for comment.

Condoms - and sex - are growing topics in popular culture, despite strict rules on nudity that mean China condom ads are tamer and more limited than in other Asian markets. Young people also chat about the subject online - though they often use code.

Pornography is illegal, but China's young find ways to watch it nonetheless, with an online vernacular growing around its availability. People who know about the best illegal sites are called "old drivers", who help others to "find the car".

The government is helping too, spurred by efforts to raise awareness of illnesses such as HIV/AIDS through high-school sex education textbooks and campaigns with university students. Peng Liyuan, China's popular First Lady, actively campaigns to raise awareness of HIV/AIDS and how to respond to it.

SEXUAL AWARENESS

China's conservative attitude, ushered in by the Communist Party when it took power in 1949, has slowly been changing -- helped by growing affluence, more overseas travel and exposure to foreign popular culture.

It's far cry from where China was even two decades ago, when more permanent contraceptive techniques were used once a couple had their first child to avoid further pregnancy. Even now, sterilization and IUD coils are still far more prevalent methods than condoms.

"Sexual awareness including contraception is slowly rising," said Wang Xiaoshuang, founder of sex education firm Greenxxoo, pointing to premarital sex which is now broadly accepted. "Twenty years ago that sort of behaviour was taboo."

Wang said that there was an increasing awareness of "safe sex" because of HIV/AIDS prevention campaigns, though added tough rules around advertising condoms meant most brands had to stick to online marketing.

The more open attitude could see China's condom market more than double in size by 2024 from $1.8 billion in 2015, according to a report from Transparency Market Research.

China's sexual revolution is still nascent, though. This week a Chinese "female virtues" teacher caused a social media storm by saying women should not wear short dresses and should save themselves for their husbands.

"Everything thinks there's a big trend towards buying adult products... But there is still a big swathe of people here who don't get it," said a sales worker surnamed An at an adult products store in Shanghai.

He said growth of the broader "adult" market was steady rather than stellar, but that young people were now starting to help change things. "The young want something fresh, they're not just clinging to conservative views," he said.

Attitudes, including those about sex before marriage have changed drastically over recent decades, with most people now supportive. But sex education - key to driving contraceptive demand - still has some way to go, said student Zhang.

"When I was younger my parents did talk to me about contraception and some basic things about sexually transmitted diseases. Everything else I had to go and find out for myself."

(Reporting by Adam Jourdan and SHANGHAI newsroom; Additional reporting by Tom Westbrook in SYDNEY; Editing by Martin Howell)

By Adam Jourdan