In a break with her standard practice, Cindy Sherman does not appear in the 1989 Sex series; instead, pieced-together medical dummies form a substitute for the human subject.
While the artist is visually absent from these works, Sherman's voice is more than usually specific.
The photographs function partly as a protest against US Government cuts in arts funding at the time, as well as attempts to censor the work of artists such as Robert Mapplethorpe and Andres Serrano; although the images clearly suggest sexual acts, the absence of live nude models makes them virtually immune to censorship laws.
Sherman's point, however, is that regardless of what isn't shown, her images are obscene in a very real, morally significant sense.
The use of mannequins completely dehumanises the (mainly) female forms, rendering them little more than grotesquely disembodied objects.
Akin to the nightmareish visions of horror movies, the images are highly disturbing in their implications of emotional detachment and broken, severed body parts.
Calls for censorship routinely target 'offensive' depiction of the human body while sanctioning images of a far more insidious nature.
What Sherman powerfully suggests here is that any system unable to detect or legislate against the troubling nuance in her images is equally unsuited to judging the frequently fine line between pornography and art.
With his frequent focus on cultural taboos, US photographer Andres Serrano is no stranger to controversy.
In the late '80s, his work became embroiled in political attempts to effectively censor art - as well as furious counter-efforts to prevent the curtailment of artistic expression.
The fact that this freedom remained in place is amply demonstrated by Serrano's highly graphic History of Sex series, a collection of portraits depicting many different modes of sexuality.
While some would argue that Serrano's attraction to iconoclasm and controversy sometimes seems as much about notoriety as serious investigation, few would deny his formal photographic skills.
Superb composition and an ability to focus coolly yet dramatically on his subject are particularly evident in the History of Sex.
By producing each portrait with immense care, Serrano not only showcases his skill, but effectively states that all of the practices or individuals depicted are equally worthy of respect.
The result is a series of images which, however marginal or even extreme they may seem to some, to others are dignified and worthy records of their own sexuality.
Catherine Opie is well known for photographs that document both her own sexuality and that of other gay women.
A series of images from the mid-1990s depicts friends and associates from the San Francisco S&M and leather scene, a subject that invites some comparison with Mapplethorpe.
While Opie has a very different approach to the formal concerns of photography, she similarly seeks to represent and dignify a subculture that is frequently misunderstood.
Opie's unsettling self-portrait Pervert is, on one level, an unsettling record of alternative sexuality: hooded, with rows of needles piercing both arms, the word 'pervert' has been freshly cut into her chest.
In fact, the portrait is at least partly ironic, its deliberately confrontational stance a response to Opie's perception that the S&M scene was increasingly regarded by many gay peers as somehow deviant.
By literally branding herself a pervert and donning fetish paraphenalia, she cleverly plays up to expectation: this is how someone whose sexual tastes are not 'normal' should normally look.
The notion of conformity with regard to sexual orientation is a consistent theme in Opie's work.
Her 1998 series Domestic, for example, portrayed long-term female couples in the familial setting of their homes. As Opie has said:
"The discourse with family is usually heterosexual, and I wanted to create another context to begin to think about family, both on a personal and political level."
Yet although sexuality has formed a substantial and important aspect of Opie's work to date, she brings her formidable skills to bear on a wide range of subjects reflecting themes of community within the actual and metaphorical American landscape.
"I am an American photographer," she has stated. "I have represented this country and this culture. And I'm glad that there is a queer, out, dyke artist that's being called an American photographer."