Bryony Kimmings, Soho Theatre

Internet porn, the sexualisation of childhood and the objectification of women are so commonplace in Western society that they go mostly unmentioned and unchallenged, even in the arts.

So thank goodness for performance artist and comic Bryony Kimmings, who not only mentions and challenges these pernicious forces in so-called civilised society, but in Credible Likeable Superstar Role Model, an award-winning show first seen at Edinburgh Fringe, fashions an entertaining show around them.

It was created from a very personal perspective. Kimmings recently started taking an active care role in the life of her nine-year-old niece Taylor – who performs the show with her - and she was shocked by the kind of stuff Taylor watched, alone, on television and the internet after school each day. Highly suggestive music videos, constant messages about female bodies and “beauty” and the sexualisation of boy/girl behaviour, not to mention girls of her age – tweenies – being targeted by advertisers.

If Kimmings's objective is to make people go away and consider the issues more deeply, then I suspect she has succeededThe show starts with the two of them dressed as if characters in Charles Kingsley's The Water-Babies, in pantaloons and ruffed collars. But as they dance to Jessie J's "Domino" (“I'm feeling sexy and free”), we see Taylor's seemingly innocent rendition alongside Kimmings's more overtly suggestive one, and we realise there's not a huge difference in their moves.

Then they give their testimonies: Taylor thinks that pop stars just want to sell her stuff and she doesn't understand much of what they say, while Kimmings talks about her self-centredness and her previous shows about sex and abusing alcohol (doesn't worry, Taylor wears sound-blocking headphones for these sections of the show). Studies 50 years ago, Kimmings says, showed that nine-year-olds wanted most of all wanted to be kind when they were grown-ups; in 2010, their ambition was to be famous.

So we learn how Kimmings decided to create – in the absence of the real thing – a positive, healthy role model for her niece and her friends. She asked Taylor what kind of role model she would like to see, and so Catherine Bennett (Taylor likes the name), a dinosaur-loving palaeontologist who likes tuna bake and riding her bike, was born. Kimmings recorded some songs (now on YouTube) as the blonde-haired, bright singer who talks about politics and stuff like feminism, and goes into schools to engage with children of Taylor's age; maybe some of them may consider that doing a Miley Cyrus (whatever you think of her twerking) isn't the only way to express your talents.

Kimmings's love for Taylor is obvious and this piece is shot through with a genuine concern for her and our children's future. But although there are many funny and/or thought-provoking moments, as a piece of comedy or theatre this show doesn't entirely deliver; it's rather unfocused and has moments when it feels frustratingly like a meaty subject is being given too cursory a treatment. But if Kimmings's objective is to make people go away and consider the issues it raises more deeply then, judging by the comments as people were leaving the auditorium, I suspect she has succeeded.

If you agree that we should try to give children decent role models in the arts, then you may want to follow Catherine Bennett @RealCB and spread the word – because who knows, a social revolution may be happening.

• Bryony Kimmings is at the Soho Theatre until 26 October