A visitor takes photos using his smartphone at a sex culture fair in Guangzhou, Guangdong province, in November, 2015.[LIN HONGXIAN / FOR CHINA DAILY]

In addition to the changing sex attitudes of Chinese people, Wang said China's gender imbalance was also a key factor that is driving growth in the sex doll business.

"China's decades-long one-child policy and a traditional preference for sons has led to a severe gender imbalance, with some men finding it hard to find girlfriends," Wang said.

According to the National Bureau of Statistics, China had more than 700 million men by 2014, or 33.76 million more than the population of women.

Specifically, the rate between unmarried men and women born in 1980s was 136:100, according to the NBS.

"The gender imbalance has brought about great potential for market growth of sex toys," said Wang.

According to Lin Degang, chief executive officer of Chunshuitang, one of China's leading sex-toy business-to-customer service providers, more than 60 percent of online sex toy buyers are men, with most born in the 1980s and 1990s.

"Young people, especially men below the age of 40, have developed strong demand for sex dolls," said Lin.

Chunshuitang's sales of sex dolls in 2015 were almost 2.5 times that of 2014, according to Lin.

In addition to sex dolls, online sales of other sex accessories, including condoms, sexual lingerie, dildos and dancing eggs, have increased rapidly, according to Lin.

"Conservative attitudes toward sex are no more widespread. As a result, the sex toys industry has grown at a very fast pace," said Lin.

Liu Qianghua, a sex toy shop owner in Guangzhou, said a growing number of Chinese young people have developed "healthy attitudes" toward use of sex dolls.

"Most people initially buy a doll just for sex. Then they will start to make them more beautiful by dressing them up in different costumes or give them names," said Liu.