As an increasingly sexually aware Harry Potter hits our screens, Jon Hozier-Byrne looks at how sex has become an essential part of our movie-going experience

Sex. Sex, sex, sex, sex. Regardless of the film, regardless of the genre, we are conditioned to expect sex as a fundamental trope in almost every film. Almost every film has a sexual element, be it horror or high-brow drama, or be it comedy or documentary. Even kids films incorporate sex to some degree.

Why is sex such an essential component of movies? Why is the very hint of sex something that attracts people to theatres? To what degree are we being manipulated, and to what degree are we perfectly fine with manipulation if we get the vaguest hint of a sexual subtext?

The cliché is true: sex sells. This is a long way from groundbreaking journalism, but it’s worth considering the ubiquity of sex in movies since the medium’s inception. Early silent films like Thomas Edison’s Annabel’s Serpentine Dance (1884) were essentially 30-second long vaudeville attractions – this film in particular depicted an attractive young woman dancing with long strands of cloth.

When we look at it now with a superimposed piano score and it’s original, painstaking hand colouring, it becomes movingly simplistic and beautiful. At the time, however, it had a sexual appeal to it that is completely lost to contemporary viewers. In fact, the film became increasingly popular as rumours of an all-nude version began to circulate. From the very beginning, sex played a key part in the appeal of the cinema.

Cinema is an art form built on voyeurism. More than any other medium, cinema lends itself to the inherently pseudo-sexual thrill of watching something you are not meant to see. In most traditional forms of cinematic narrative, the role of the viewer is passive – the audience are not directly involved or referenced by the characters onscreen.

We are a fly on the wall; we are peeking just outside the windowsill. Everything that happens we are not supposed to be witness to and it is that inherent conceit – that the viewer is allowed be both the target market and the voyeur – that gives cinema its capacity to capitalise on that most basic of human needs.

That said, Hollywood studios did not invent sex. It has essentially been a trope in our storytelling mythos for as long as there have been stories. According to the comparative mythologist Joseph Campbell, the vast majority of all epic stories, from the Odyssey to Star Wars, all culminate in the rescue of the princess, or of a wedding, symbolic of sexual union.

Often, it is the essential impetus the hero has for beginning his quest in the first place, just as Leia’s distress signal was what made Luke Skywalker start his journey in the first place. Not only is sex something we look for as an added bonus in our movies, like explosions or comic relief – it is a vital part of the storytelling structure – and that’s just the sub-textual sexual elements.

What do Halle Berry, Angelina Jolie, Salma Hayek, Heather Graham, Jessica Biel, Christina Ricci, Anne Hathaway, Reese Witherspoon, Jennifer Connelly, Kate Beckinsale, Penelope Cruz, Keira Knightley and Drew Barrymore have in common? Yes, they’ve all been topless on camera in one film or another.

If you got that right, shame on you, you pervert. If you didn’t know that, don’t worry, I’ll wait for you to come back from desperately searching for a Wi-Fi connection.

Everyone back? Good. Now, what could possibly possess actresses of their calibre to bear all on film? The answer is, of course, money.

You know how many people saw Closer because they were intrigued by the amazing possibilities of having both Julia Roberts and Jude Law in the same film? That’s right, nobody. The single biggest draw that film had was Natalie Portman stripping in a pink wig. Forget the years spent by the screenwriter in perfecting each character. Forget the direction, forget Clive Owen’s brilliant performance – all it came down to was Queen Amidala in sparkly underwear.

It would be easy to brand the emphasis on sex as essentially exploitative, as it is almost always female nudity that features in major Hollywood films. This common viewpoint, predictably, only tells half the story. Male sexuality is exploited just as much, if not more, then the female equivalent.

The Twilight saga is sold, not on the puddle-deep plot, but on Taylor Lautner’s chest ripples. Men are as objectified and interchangeable in film as women are, it’s simply the way that sexuality is handled that changes. It is perceived, perhaps incorrectly, that men want none of the nuance women do in their objects of desire.

Perhaps we are simply less complicated creatures when it comes to what we find attractive, perhaps we are simply less picky. After all, Megan Fox is one of the most lusted-after women in cinema, and she has a face like the illegitimate progeny spawned from a night of angry lovemaking between a particularly toothy cat and Daniel Radcliffe.

It’s hard to condemn the use of sex in film, as it is seemingly such an essential aspect of what makes movies appealing. It is simply worth noting the effect it has on us. For some reason, light projected on a wall in the shape two intertwined attractive people can make us feel as though we’re somehow involved – such is the power which sex in cinema has over us.