For decades, no big-box-office, adult-oriented Hollywood movie was apparently complete without a sex scene, from Don’t Look Now to Basic Instinct. Yet it appears that erotica is now dying out in mainstream cinema.

A critical analysis published in the Washington Post last week noted: “Sex is disappearing from the big screen, and it’s making movies less pleasurable.”

It said that a new summer pattern has emerged: the release of several European-produced festival and arthouse films – often, like this year’s French drama Mektoub, My Love: Intermezzo, heavy with action – followed by a season of sexless Hollywood action and family films.

Lost between those two options is the classic sex scene. So no more Don’t Look Now with Julie Christie and Donald Sutherland; no 9½ Weeks with Kim Basinger and Mickey Rourke; no Dangerous Liaisons, The Postman Always Rings Twice or Mulholland Drive ... the list goes on.

“Once a staple of high-gloss, adult-oriented, mainstream movies,” the Washington Post wrote, the sex scene “has been largely forgotten and ignored, recommitted to the very esoteric margins it sprang from generations ago”.

But why? According to academics and close observers of Hollywood culture, the reasons are multifarious, and suggest that the movie business is going through a profound realignment of priorities backed by broad cultural, political and legislative changes.

According to Stephen Galloway, a columnist at the Hollywood Reporter, the changes are primarily economic: Hollywood is simply no longer in the business of making mid-budget character dramas that might or might not include physical bonding. Instead, movies must appeal to the “four quadrants” – male and female, over and under the age of 25. “Weirdly, it’s not a new puritanism – Hollywood has always been puritanical. Its about economics,” says Galloway. “Include sex and you’ll get an ‘R’ rating, and that means no kids: that’s not going to bring in a four-quadrant audience.”

The current exceptions, or at least aberrations, seem to be musical dramas involving homosexual love: witness the success of the Elton John coming-out-and-getting-famous drama Rocketman, or the Queen biopic Bohemian Rhapsody, which has reportedly produced a billion dollars in business for its producers, the group’s drummer and guitar player.

Mickey Rourke and Kim Basinger in 9½ Weeks (1986). Photograph: Allstar/MGM/Sportsphoto

But no discussion of sex in the cinema in 2019 can take place without reference to #MeToo – the movement that has brought profound changes to what women can insist on in their contracts. “Women feel far less compelled to agree to nudity, and it’s empowered them to say no,” says Galloway. In the current environment, lawyers for actors are demanding more specific, iron-clad protections in “nudity riders”, including the ability to sue for leaked footage.

Part of the change, again is economic. Female actors, if they’re lucky, can pick up lucrative fashion and beauty endorsements, both of which demand careful image preparation and maintenance. Having your latest sex scene blasted across the internet is hardly an endorsement of sophistication.

The changes, Galloway says, apply equally to television, where despite the greater freedom of content provided by Netflix and HBO, the classic sex scene is still something of a rarity.

Where there are exceptions, they can be startling. The new drugs-and-sex teen drama Euphoria starring the former Disney star Zendaya is a case in point.

According to reports last week, Euphoria includes graphic nudity (including 30 male exposures in one episode), violence (a statutory rape involving a 17-year-old trans girl) and sex scenes involving choking and drug use, including Zendaya’s character herself overdosing.

“There are going to be parents who are going to be totally fucking freaked out,” Euphoria’s creator, Sam Levinson, son of director Barry Levinson, told Variety last week.

But, again, liberating 22-year-old Zendaya from her Disney-princess prison with a shocking coming-of-age series is not quite equivalent to the behaviour that female actors are now taking a harder stance against. From producers demanding unnecessary nudity to the allegations of routine “casting couch” sexual abuse that are likely to be heard by a Manhattan jury when the producer Harvey Weinstein goes on trial in September, the mood in the movie business has shifted.

Professor Linda Hirshman, author of Reckoning – a major new study of sexual abuse and harassment that traces the origins of the #MeToo movement to the death of Mary Jo Kopechne in Ted Kennedy’s car at Chappaquiddick in 1969 – argues that the roots of the current anti-sex mood go back to the restoration of the British monarchy in 1660.

It was then that women were first allowed to take the stage and treated almost by definition as being sexually available. Fast-forward 300 years, and Hollywood, Hirshman writes, “was like Restoration English theater on steroids”. Or, as Marilyn Monroe once noted, the men she knew saw Hollywood as “an overcrowded brothel, a merry-go-round with beds for horses”.

But returning to the days before 1660 may not be what today’s actresses have in mind. In her research for Reckoning, Hirshman says several actresses told her that, although they objected to being pressurised to appear nude, the fact of nudity itself was not the problem.

Donald Sutherland and Julie Christie in Don’t Look Now (1973). Photograph: Moviestore/Rex

“They complained bitterly about being abused by their male co-stars when they appeared in sex scenes prior to the #MeToo movement,” Hirshman says. “In some cases, male co-stars took advantage during sex scenes, touching them where it wasn’t necessary for the scene.”

Hirshman believes actresses could have sued years ago under America’s 1964 Civil Rights Act on the grounds of being made to work in a hostile environment. “Of course, it would have been the end of their careers, and of course they didn’t want to sacrifice their ambitions.”

She believes the turning point came in 2016 with the Fox News anchor Gretchen Carlson’s sexual harassment lawsuit against the head of her network, Roger Ailes – a landmark case that helped dispel the stigma of bringing a lawsuit. The floodgates opened. But the political and legislative environment matters too: Hirshman points out that California has very advanced employment-equality laws.

Female stars such as Reese Witherspoon and Meryl Streep have joined the effort for sexual-equality education, helping to turn the tide against harassment in an industry where career success and failure for aspiring actresses seems to turn on the unknowable machinations of producers, directors and agents, most of whom are male.

Just maybe, then, the death of the contemporary sex scene has deeper roots for women in the acting profession than are readily obvious, Hirshman says. “We can speculate they might be exercising a scintilla of the new power that they now have and putting limits on their exposure to abuse.”

X-rated scenes

Secretary (2002)

Maggie Gyllenhaal and James Spader portray BDSM roleplay

9½ Weeks (1986)

Mickey Rourke and Kim Basinger explore a brief but graphic and obsessive affair

The Piano Teacher (2001)

Michael Haneke directs Isabelle Huppert and Benoît Magimel in an exploration of sado-masochism

Last Tango in Paris (1972)

Marlon Brando’s obsession with Maria Schneider becomes a test of sexual disassociation.

Don’t Look Now (1973)

Rumours circulated for years that Donald Sutherland and Julie Christie’s frank sex scene was not simulated

Blue Is the Warmest Colour (2013)

European in origin, the lesbian love story includes a seven-minute sex scene

American Psycho (2000)

Mary Harron’s brilliant but profoundly unfriendly take on male sexual sociopathology

The Outlaw (1943)

Jane Russell hits the hay as the feisty Rio McDonald in the role that made her famous

Black Swan (2010)

Darren Aronofsky’s ballet melodrama features a fantasy lesbian scene with Natalie Portman and Mila Kunis