'It is only shallow people who do not judge by appearances," wrote Oscar Wilde.

It sounds like a joke, but he was not being entirely facetious. After all, he was one of them. Like it or not, in his day, and even more in our own, the way someone looks matters, far more than it should. We may agree that you should never judge a book by its cover, yet again and again that is what we do. The handsome, the beautiful, the thin and the tall walk off with the top jobs and wealthiest partners. As a study of Fortune 500 companies revealed, a third of American CEOs are over six feet two, have full heads of hair, a deep voice, and walk with an athlete's swagger. Few are women, and fewer are fat. It wouldn't be surprising if the outcome of criminal trials revealed a similar bias against the plain and unattractive.

Yesterday, Nicola Sturgeon tacitly acknowledged that she is braced for as many comments about her appearance as on her performance should she be elected First Minister. "I should be judged for my work as a politician," she told a newspaper, "not how I look. You've got to be prepared to read in the papers about how dreadful you look and how horrible your hair is or if you've put weight on or something... I accept it as part of the world I live in and try not to let it bother me too much."

I applaud her sang froid. Her tone suggests resignation about a fact of life women in public roles must face, rather than resentment at the unfairness of a country more fascinated by the cut of a politician's suit than her thoughts on the welfare budget.

Sturgeon also recognises she will be obliged to discuss highly personal issues in a way no man would either expect or tolerate. Though offensive remarks have been made about Alex Salmond having no children, it would be a brave - perhaps suicidal - inquisitor who dared ask him about that. Yet as most childless women are aware, complete strangers feel free to raise this intensely sensitive subject with them, as if everyone has a right to know. How much worse, then, if the answer will be broadcast to millions. Nor are such intrusions confined to politicians. Actresses, bankers and businesswomen are all expected to field questions so personal even Jonathan Ross would think twice before asking.

The scrutiny such women face is so commonplace that we seem almost blind to the crassness of it. Blame the media if you like, but nobody continues to buy a magazine or tune into a show if they find its material offensive. The gauntlet celebrities walk beneath the telephoto lens is abhorrent, cellulite, wrinkles and flab treated as if they were a list of criminal charges and paraded on the front of trashy rags to boost schadenfreude as well as sales.

Not that men are wholly immune. After being likened to Nick Park's cartoon character Wallace, Ed Miliband worked on his image, although the problem lay not with his looks but his policies. Even so, he can sleep easy knowing that as he ages nobody will criticise him when he goes bald. Meanwhile, Hilary Clinton was savaged for an unflattering hairstyle, Angela Merkel mocked for wearing an outfit first seen years ago, and the Duchess of Cambridge's post-baby bulge became the talk of the water cooler.

Sensible women do not waste energy fighting the system, but learn their time is better spent growing another skin rather than exfoliating. Yet it is we, their fiercest critics, who ought to take a long hard look in the mirror. Do we want a world in which the gorgeous take all? Think of all those people who have brilliant minds, personality, and ideas, but are not billboard perfect. Thanks to an ingrained level of prejudice that goes largely unchallenged in this supposedly politically correct age, some of the country's most valuable citizens are excluded from positions of power. They will be kept out or held back either by employers, or the electorate, or by their own fear of the cruel comments they might have to endure should they reach the top.

Until this corrosive culture changes it seems not only Oscar Wilde was right, but F Scott Fitzgerald. There are the beautiful, and then there are the damned.