You're watching a movie with a couple of friends and that uncomfortable sex scene comes on screen. The actors aren't really having sex though, so it's okay to sneak a peek. Or are they?

Simulated sex scenes in films have become the norm in cinema. The glistening of sweat on the actors' shoulders, the way the sheets fall precisely over the actors' privates and the rush of blood to the actors' faces are all elements of a love scene manipulated by a production crew in order to appear as real as possible. On rare occasions, however, filmmakers have employed unsimulated sex scenes, scenes that actually require actors to engage in some level of sexual activity. Not surprisingly, this technique has fueled much controversy as the line between cinematic art and pornography becomes blurred.

"We're not trying to titillate or shock," claimed filmmaker John Cameron Mitchell of his latest controversial film Shortbus (2006). However, this film has done nothing but shock viewers with its various scenes of explicit, unsimulated sex scenes. The film follows multiple New York City characters as they traverse the world of sex and love in an underground salon. The movie gets down and dirty within the first five minutes, with vivid shots of penetration and a scene of a man performing oral sex on himself and ejaculating. By the end of the film you wonder: would the film be any less moving or effective if the sex scenes were simulated? Weirdly enough, Shortbus is essentially a romantic comedy that centers on relationships. But while most mainstream romantic comedies shut the camera's lens as soon as it hits the bedroom doors, this film dives right into the bed.

When compared to the simulated sex scenes in major Hollywood films such as Monster's Ball (2001) and A History of Violence (2005), unsimulated sex scenes like those in 9 Songs produce vast visual differences. In 9 Songs, there are various close-ups of both male and female genitals, while in a steamy, stairwell sex scene in A History of Violence, the camera's focus is more on the lead actors' facial expressions; the only skin action highlights an inch of Viggo Mortensen's butt crack. Similarly, in 9 Songs, the camera makes a conscience effort to show as much penetration as possible, while during the infamous sex scene between Halle Berry and Billy Bob Thornton in Monster's Ball, a huge coffee table blocks a portion of their bodies.

Simulated sex scenes seem to be working well, so well in fact, Halle Berry had to deny allegations that her sex scene was real. Clearly, simulated sex scenes can achieve the same veracity that unsimulated sex scenes do without actually requiring the actors to tell their families to shut their eyes during the orgasm scene.

We don't have to watch an actor physically kill another actor during a murder scene to fully grasp the concept of murder. But when it comes to sex, some filmmakers feel that audiences must see it in its truest form in order to truly connect with what's on the screen. The logic behind unsimulated sex scenes, however, is questionable; if simulated sex scenes look and feel just as real to audiences, why are unsimulated sex scenes even an option? Is it just for shock value, or are filmmakers genuinely trying to achieve something of greater artistic value that can speak to contemporary societal norms?

Whatever the case may be, sex scenes, real or feigned, will continue to shock, intrigue and please us all.