Over the last 20 years, Chinese attitudes to sex have undergone a revolution – a process carefully observed, and sometimes encouraged, by the country’s first female sexologist, Li Yinhe.

“In the survey I made in 1989, 15.5% of people had sex before marriage,” says Li Yinhe. “But in the survey I did two years ago, the figure went up to 71%.”

It’s one of many rapid changes she has recorded in her career. She uses the word “revolution” herself and it’s easy to see why. Until 1997, sex before marriage was actually illegal and could be prosecuted as “hooliganism”.

It’s a similar story with pornography, prostitution and swingers’ parties.

In 1996 the owner of a bathhouse was sentenced to death for organising prostitution, Li said in a lecture to the Brookings Institution last year, but now it is widely practised. The most severe punishment these days, according to Li, would be the closure of the business.

Publishers of pornography could also be sentenced to death as recently as the 1980s, as could those who organised sex parties. Now the punishment for pornography is less draconian and swingers’ parties, while still illegal, are common. “No-one reports them, so they do not get noticed,” Li says.

As a young sociologist, Li spent much of the 1980s studying in Pittsburgh, in the US. When she returned to China, she found a country still living in the puritanical climate set by Mao.

Li Yinhe as a child
Li during the Cultural Revolution – when men and women mostly wore the same clothes

In the early years of Communist rule, writing about love was considered bourgeois. It became possible toward the end of the 1950s, Li has said, but writing about sex was forbidden until the 1980s – and even then authors could only go so far.

Li’s book, The Subculture of Homosexuality, published in 1998, could only be bought by people who had invitation letters from their employers or held senior positions.

The official position on her book The Subculture of Sadomasochism, published at about the time, was even more extreme.

“I was informed to burn all copies… But by then, 60,000 volumes had been sold out. So the burning notification was left unsettled,” she says.

Her translation of a book on bisexuality was refused by Chinese publishers, and she had to look beyond mainland China to Hong Kong, to find a publisher for her own study of polysexuality.