Oh Lourdes! What is Madonna doing? The sight of her 12-year-old daughter dragged up in full bridal outfit and red lipstick in Madge's latest video – recreating the pose from her 1985 hit song 'Like A Virgin' – had me shuddering at so many levels. Never mind the hypocrisy of exploiting your daughter – Lourdes also joined her mother on stage, on the penultimate night of her Sticky & Sweet world tour in Israel – while demanding privacy for your family.

Why is Madonna – the self-styled most original woman on the planet – so hell-bent on turning her daughter into a mini-me?

I don't mean to be squeamish. I happen to love the song. But for heaven's sake, Lourdes is a pre-teen. Madonna was 25 when she made the video for 'Like a Virgin'. Which makes all that squelchy "touched for the very first time" imagery just a bit more palatable.

Like many tactful fans, I've tried to overlook the fact that Madonna appeared to virtually bio-engineer her daughter in her own image. (Lourdes's father is Madonna's one-time personal trainer Carlos Leon.) I even forgave her recently for plundering her daughter's schoolgirl wardrobe for a Kabbalah party in New York.

But this video is a step too far. What worries me is the effect on little 'Lola' herself. It's hard enough being the daughter of a very famous woman. Child stars rarely grow up sane.

Even fame by proxy makes you unpopular with other kids, who can sniff out hype and inauthenticity. (I once casually mentioned to my 11-year-old friends that my mother would be our new French teacher at secondary school. Big bloody mistake: I was shunned for years for boasting.)

So my heart lurched when Madonna gave an interview around her English Roses book in 2003 and admitted it was inspired by Lourdes's own experiences at school. The book is about four little girls who shun a fifth, who is beautiful and clever, out of envy.

And 'Lola' actually has quite a few more problems than the average pre-teen. Her 51-year-old mother is dating a 22-year-old. That chap she rather liked, Guy, is off the scene. Her uncle Christopher sold a hilariously bitchy book about her mother. Two squealing infants have recently turned up.

And Lourdes, bless her, looks 12 going on 38. It's not her fault. When she's older, the mono-brow and bushy eyebrows will give her the dignified chic of Frida Kahlo. But she shouldn't be going round slathered in lipstick and mom's trademark, fake beauty spots, just yet. And should her mother be filmed in the same video French-kissing her boyfriend, the Brazilian model Jesus Luz, who is just 10 years older than her daughter?

Which makes you wonder: will Madonna ever be able to cede the spotlight in a natural, maternal way to her children?

I can see that the world's most famous single mother needs to make up for things a bit at the moment. She owes Lourdes. They've moved country – and schools – yet again. After a lifetime of having every programme she watched on TV vetted and every morsel she ate decided upon by her fussy mother, what 12-year-old wouldn't love to go on stage for a bit of stadium adulation?

But it's not smart – and it's not caring. This way she makes Lourdes a legitimate target for every paparazzo in the world. In her mid-20s, Madonna made the calculated decision to sell her image to the highest bidder.

She made a fortune – and changed the culture forever. But it was her image to sell.

Una Mullally is on leave