Much of Sarah Lucas' early work employs unusual materials to represent the body. These include furniture, clothing, cement, light fittings and - for the sexual organs themselves - food.
Using, for example, fried eggs to depict breasts or a cucumber to evoke a penis, Lucas is able to portray the male and female bodies in a pared down, almost minimal fashion.
Yet her choice of foodstuff, besides being visually apt, often takes the form of a bawdy, even disturbing pun, particularly with regard to the female body.
Two Fried Eggs and a Kebab (above, left) employs a meat-filled schwarma in place of a vagina, while Chicken Knickers (left) uses a raw chicken carcass to represent the female organs.
The gaping body of the bird makes for a bleakly repulsive metaphor, and more provocative still, the revealingly titled Bitch uses vacuum-packed smoked fish for the same purpose.
The fact that such pieces are intended to reflect stereotypical male responses to the female body becomes clear through works in which Lucas addresses the subject of masculine sexuality itself.
These include spoof tabloid newspapers parodying crudely sexist content, and The Man who Sold the World - a lorry driver's cab papered with fading centrespreads and equipped with a mechanical 'wanking' arm.
Beer Can Penis (below left) similarly references a boozy, macho culture that is often associated with pejorative views of women.
In her more recent works, Lucas again sets out to investigate the male gender.
The Penetralia series fuses plaster casts of the penis with reproductions of ancient stone tools or weapons (left).
'Tool' and 'weapon' are also slang terms for the penis, although since these are used almost exclusively by men, both betray a specifically masculine view of the phallus.
By referencing the very beginnings of society with her hybrid artefacts, Lucas provides a serious - and subtle - meditation on the evolution of male power, dominance and violence.
Kirsten Stoltmann frequently addresses assumptions regarding the female gender in work replete with irony and subtle visual nuance.
You Can't Handle The Truth presents an image of the artist naked, open-legged and apparently defiant beneath the pink scrawl of the titular text.
The words seem potentially aimed at idealised, 'untruthful' expectations regarding the female form - or even the artist's own body, which is curvaceous and 'real' in a way that commercial images of women are not.
What is certain, however, is that the self-portrait was upside down when the text was applied, indicating that the artist, too, is literally unable to confront her own image squarely.
Since Stoltmann seems equally disconcerted by the 'truth' she refers to, the implication is that all of us are enmeshed in some kind of dishonesty regarding the female presence. This is a work that confronts creator and viewer equally.
The Listen series (left) simultaneously celebrates and comments on femininity through a particular emphasis on the genitalia.
Collaged seashells replace the vagina on pornographic images, immediately transforming the explicit into something far more mysterious. The images' former emphasis on voyeurism - looking - becomes a request to 'listen'; a reference to the seemingly inexplicable sound heard when shells are held to the ear, but perhaps also an encouragement to listen out for 'the truth' referred to in the work above.
Semantic allusions such as those employed by Sarah Lucas are probably also at work here (in many languages various types of shellfish are slang terms for the vagina), yet sublimated into something far more delicate.
The seashell itself is something both beautiful and wondrous; an intricate, natural enclosure that harbours its own life force and source of creation within.
Exotic Treasures (above) similarly redefines pornographic images of women by pairing them with collaged objects such as finely crafted porcelain, flowers and chinoisserie.
The term 'exotic' - which is, of course, just one consonant removed from 'erotic' - is often used in adult publications to denote non-caucasian women, such as the oriental model depicted in this work.
Stoltmann's own evocation of exotica is far more expansive and literal, however, encompassing the natural wonder of a hummingbird or the intricate painting of a Chinese vase.
Within such a context, the nude images are assigned a newly feminine rather than masculine viewpoint. Equated with 'treasures' that are beautiful, delicate and of great worth, their original, crudely sexual purpose is undermined and questioned.
Sexual imagery has often played a role in work by the Chapman Brothers.
An early video work, XXXX, depicted a penis that appeared to be growing out of a man's face. Possibly an allusion to the idea that male identity is centred around the genitalia, the imagery took on more substantial form in later sculptural works in which mannequins of adolescents have noses replaced with penises, and mouths become anuses.
The figures are fused together in a monstrous act of apparent genetic engineering. Blandly near-identical, the de-personalisation of the countenance into a literal 'fuck face' deprives the figures almost entirely of facial expression and transforms portraiture into pornography.
Verbal communication is also rendered impossible, the anal 'mouth' prompting associations with violation or cynically punning on the phrase 'talking shit'.
The works are intended to provoke and shock, and do not seek to investigate sexuality itself in any meaningful way. Yet the iconoclastic use of genitalia is pivotal to the sculptures' grotesque appearance, an apocalyptic vision of the human rendered obscene.
Koh frequently references gay male sexuality, often making use of erotic imagery gleaned from magazines and the internet.
While his practice has sometimes caused controversy - a small sculpture of Christ sporting an erection provoked outcry when exhibited (as part of a larger installation) in 2008 - his iconoclasm is rarely as obvious or heavy-handed, directed instead towards taboos so subtle we may not have even considered them as such.
One instance of this is the delight Koh takes in subverting the very basis of pornography, making it the focus of camply romantic, rather than purely sexual, fantasy.
Explicit images of tough-looking young men are, for example, printed on lilac-hued paper; porn models reproduced in soft focus, or booklets depicting a series of 'hard-ons' described as 'dreamy' and wrapped in 'baby-blue' tissue.
With the sexual element of his chosen imagery treated simply as a given, Koh's primary interest is apparently channeled into a sentimental reading of hard-core content that is as unorthodox as it is surprising.
Pornography is not conventionally interpreted as some kind of romantic fantasy, and for many, Koh's subversion of sexual context is likely to prove more disconcerting than the content itself.
At other times, Koh actively ridicules fundaments of male sexual identity.
The equation of the penis with virility is, for instance, startlingly negated by Outfit for my Cock, a work which the artist describes as:
"a replica of my cock mounted on a minimalist stand, an outfit over it to keep it warm, a bottle of Chanel no.5 perfume, to be spritzed in heavy doses on the outfit."
The fact that the 'outfit' in question is essentially a wig carries obvious associations with drag, further undermining the male presence.
While the subject of the work is nominally the artist himself, Koh's humorous disregard for conceptions of masculinity is a wider riposte aimed exactly where it's felt the most.
Koh's consistent refusal to abide by - or possibly even recognise - unwritten convention forces us to reappraise the basis of such attitudes.
By consistently re-envisaging the 'obscene' as a source of romantic or playful fantasy, pornography in its generally accepted sense simply doesn't exist in Koh's vision of the world. His stance is far more radical than has often been assumed.