It was only a matter of time before Disney transformed Merida, the heroine of Brave, hailed by many as their first feminist princess, into a female archetype. The Princess franchise, which came into being in the early 2000s when then-chairman Andy Mooney saw the marketing potential in presenting celebrated Disney princesses as a unit, isn't known for its nuanced portrayal of modern femininity. The cartoons have never encouraged ambition in little girls, with character traits limited to marriageability (Jasmine, Cinderella), beauty (Belle, or Snow White, whose appearance is such that jealous women seek to annihilate her), or submission to drastic physical changes in order to attract a man (Ariel). Disney princesses never really did have much to offer. Until Merida.

To be "crowned" Disney's 11th princess, the Scottish, red-headed Merida (who refuses to marry the prince) has been treated to the kind of airbrush job that magazine pages habitually go in for. Suddenly her waist is slimmer, her eyes are doe-like with heavy lashes, and she's subtly grown breasts. As Peggy Orenstein, author of Cinderella Ate My Daughter, pointed out: "In the end, it wasn't about being brave at all. It was about being pretty."

It's unsurprising that those parents who initially praised Disney for its creation of a princess who looked like a real girl are dismayed, to the point where A Mighty Girl, a resource site that helps parents find books and toys that encourage positive feminine role models, has launched a petition. Already it has received more than 100,000 signatures.

The importance of having visible positive female role models should not be underestimated. Seeing strong, independently minded female characters is vital to both boys and girls if they're ever going to grow up viewing their fellow human beings as subtle and multifaceted. It's especially vital for girls, because, as campaigners keep telling us, you can't be what you can't see. I wish that Brave had been around when I was a little girl, to show me an alternative to all those big-skirted damsels in distress, with their "some day my prince will come" and their serenading of small mammals.

As someone whose parents fought against but eventually yielded to Disney princess culture, I know how persuasive these myths can be. When I was six, all I wanted was to be a princess, but despite their popularity in the playground, my parents made a concerted effort to temper every Disney cartoon with a more positive portrayal of womanhood. We know that the female characters in fairytales have not always been so two-dimensional, and while I'm not suggesting that we return to the originals (you can't really blame Disney for shelving the rape and the cannibalism in Sleeping Beauty), an alternative adaptation of the Hans Christian Andersen Little Mermaid tale I watched on VHS certainly provided another perspective (namely: don't try to change yourself for a man, ever, or you'll die and then end up as foam).

Similarly, books such as the Tough Princess and Jane and the Dragon, both of which I loved, provided me with confident, scrappy women to look up to. When I wanted to dress up as a princess for a fancy dress competition, my mum compromised by styling me as "a Celtic princess" somewhat like Merida. I had a shield and a spear, as well as a crown.

Emma as Amelia Earhart. Photograph: Jaime C Moore

In fact, one of the most effective ways of challenging the Disney princess myth is through dressing up. Instead of stumping up £30 for a shiny, polyester concoction from the Disney store, why not investigate other options, as Texan photographer Jaime C Moore did last week by dressing her five-year-old Emma as "a real women for my daughter to know about and look up to". Thus we see Emma as aviator Amelia Earhart, fashion pioneer Coco Chanel and, perhaps most touchingly, the president of the United States.

Emma as Coco Chanel. Photograph: Jaime C Moore

"We had so much fun picking out the costume pieces and through each woman's portrait I would tell her about each incredible woman. Learning of Amelia Earhart seemed to be her favourite," said Moore. "Just the idea of her dressing like the first female pilot to fly across the Atlantic and Pacific Ocean thrilled her. I love her facial expression in the photograph, I took the shot as I was cheering 'Emma you just flew a plane, by yourself, over the Ocean!'. In her eyes I see so much pride and confidence."

In the end, that is what matters; pride and confidence. It's a shame that Disney couldn't be as brave.