Jayne Dowle: We don't need shortlists, just women good enough to make it on their own

When my babysitter, Katie, who is studying sociology A-Level, asked me to fill in a questionnaire about "employment and gender", she rolled her eyes in amazement.

It was a long list of careers with a tick box asking whether each was a "man's job or a woman's job". With the exception of professional footballer – and knowing plenty of excellent female football-players, I had to be careful – I ticked "man" and "woman" for every job. Midwife, gardener, firefighter, lawyer…. and I only ticked the male footballer box because the women's game is so sidelined it is a lucky girl who gets to make her living at it.

I can't remember if "member of Parliament" was on the list. But Prime Minister was, and of course, I ticked both boxes. Katie, who is only 17, looked even more surprised. So I had to tell her about Margaret Thatcher. I wonder then, if only for people like Katie, who see the upper echelons of politics as a boys' club, if all-women shortlists for political candidates are actually a good idea.

If they do happen – and a cross-party conference is calling for all parties to be forced to field more women – at least teenagers will realise that girls are capable of politics.

It would be the only justification. As I pointed out to Katie, there can't be many things that me and Margaret Thatcher agree on. But there are definitely two; that women can hold down a meaningful job as well as bringing up a family, and that women should always be judged on their own merits and abilities.

As an aspiring politician, Thatcher tried and failed several times to be selected as a candidate before becoming MP for Finchley in 1959. Whatever your political inclination, you can't help but admire her for sticking at it.

You can imagine what personal slights and sexist comments she had to endure. But I bet you anything that the last thing she would have wanted was to be put on all-female shortlist just so she could get elected.

I'd love to know what she thinks of David Cameron's support for the idea. It's not surprising he faces rebellion from local party activists.

When I think of other stand-out female politicians, not all of whom I agreed with politically or personally – Barbara Castle, Mo Mowlem, Shirley Williams, Betty Boothroyd, Edwina Currie – I can't think of one who would have wanted to get to Westminster because she was a woman helping to make up some spurious "quota".

So when Harriet Harman bangs on "increasing diversity in Parliament" to "reflect the country in which we live and the public we serve", I want to scream. What exactly does she think she means? Does she assume, in this day and age, that young men, keen to go into politics, do not have any understanding of what women might want? This is a great insult to men, who have a hard enough time pleasing women already. And surely diversity in itself does not constitute some great achievement, by which the world of Westminster will be transformed into a haven free of gender-bias and discrimination?

How would we measure this diversity? If, by some miracle, there are exactly the same number of male and female MPs after the election, will each law that is then passed please all of the people all of the time, because the politicians making it are so "diverse"? I would have thought that Ms Harman has been around long enough to know that this is about as likely as John Humphreys giving her an easy ride on the Today programme.

Diversity for its own sake achieves nothing, and actually demeans the minority it intends to promote. Dare we mention the "Blair Babes", the 101 female Labour MPs elected at the 1997 General Election? With some exceptions, including Harriet Harman, an embarrassing proportion decided that politics was not for them, and left the government.

One of the major arguments in favour of all-women shortlists is that no-one has yet come up with a better idea to encourage more women into parliament. But should it matter? Surely, the best candidate is the best candidate, regardless of their sex.

If a woman really wants to make it, she will – just as Margaret Thatcher did. And it's that kind of determined, pushy, trail-blazing kind of woman we want to represent our interests.

Not some politically-correct Harman clone bleating "shortlist" and "diversity" when she should be wowing us all with her intellect, ambition and sheer force of personality.