It's not often I leave an exhibition feeling nauseated, but something in the combination of fried eggs, toilets and floor-to-ceiling images of disembodied genitals did the trick. Sarah Lucas' aggressively sexual retrospective at Whitechapel Gallery is not for the faint-hearted, though after wading through a preponderance of penises and toilet-humour sculptures, pinning down exactly what is going on underneath Lucas' salacious veil is not as easy as it seems.

Lucas rose to fame alongside Damien Hirst and her partner Gary Hume as one of the leading figures in the Young British Artists generation in the 1990s. Known for her bawdy humour, use of collage and found objects, and her self-styled androgyny, she forged a reputation for herself as one of the most shocking artists of her time.

And there is a lot of shock value here: in most of her pieces, human bodies are reduced to crude approximations of genitalia. Her 1995 sculpture Bitch is brutal and uncomfortable in its portrayal of a woman, made up of a table, T-shirt, melons and a smoked fish. Two Fried Eggs and a Kebab (1992) works along the same lines, placing a pita full of decaying meat in the position of vagina. It's difficult to say whether these works are engaging with feminism, decrying the misogyny and objectification underlying gender relations, or simply uncovering the unsavoury aspects of human sexuality. Men don't get off much more lightly under Lucas' hand – an entire wall is papered with enlarged photographs of penis tips floating in some sort of glutinous soup, and you literally cannot walk through the second exhibition room without confronting larger-than-life images of a headless man playing with cans of lager, biscuits, and his naughty bits. (How on earth did Lucas convince Gary Hume to pose for those photographs?)

Sarah Lucas clearly relishes lifting the veil of propriety; sticking a finger up to society and its conventions, its sexual norms and gender categories – but surely more is at stake here than an adolescent rebellion. There are rooms full of Duchamp-inspired acrylic toilets; concrete blocks and work boots; more images of penises than most people see in the flesh over the course of their entire lives; and chickens, greasy hams, melons and fried eggs time and time again standing in for bodies. After wading through all these, I began to wonder whether this exhibition was rather the portrait of a Swiftian misanthrope, both confronting and revelling in a deep disgust with the human body and its animal effluvia. Yet, perversity and revolting sculptures aside, there is also a lot of humour here – in collages of extraordinarily explicit personal ads from bored housewives (and even grandmothers), and in Lucas' own playful self-portraits with eggs and bananas.

Shock for its own sake, if that is at least part of what is going on in Lucas' work, relents slightly in the upstairs room. Here, her more recent work moves away from visual aggression and towards a more reflective mood. If these later pieces are not yet a sign of an end-of-career maturity – the room remains dominated by gigantic plaster penises – they are significantly tempered by contrast to the brutal and vulgar sexuality of her 1990s work. A collection of cast bronze figures, contorted like balloon animals polished to a high sheen, were included in this year's Venice Biennale. Here, they are just as gleaming and sensuously erotic: the intertwined and androgynous bodies suggesting a much more tender and optimistic view of sex. Perhaps there is hope for our dirty, squidgy, sex-obsessed human race yet.

Sarah Lucas, at Whitechapel GalleryKate Mason's review of Sarah Lucas at the Whitechapel Gallery.4