Women don't have to overdo the argument about their input into economics with dodgy statistics or ludicrous claims of how brilliant women are, writes LUCY KELLAWAY.

ON SEPTEMBER 4th, 2006, a company that is now in the FTSE 100 appointed two women to its board as non-executive directors.

Since that day, the share price of that company has gone up by 18 per cent, while the market has gone down by 28 per cent.

As one of those women happens to be me, I would like to argue that the first fact has brought about the second. But since being a non-exec means one has to look hard at numbers and try to be sensible about them, I feel obliged to point out that the outperformance is due to other things: the fact that two women have pitched up for about nine meetings a year has precisely nothing to do with it.

However, this outperformance makes me a part of a new statistical orthodoxy that claims to have established a definite link between women and money. In the past two weeks, this link has been thrust down my throat twice. First, at a dinner in London last week for senior working women, this link was simply stated as a fact. And then, more forcefully, it was stated in a new book called Womenomics written by two US television presenters.

The book’s central tenet is something called the “asset-to-oestrogen” ratio – the idea that companies with more senior women are more profitable. This ratio makes me feel queasy for three reasons. First, it is yucky. Second, it is ageist, as women who have come out of the menopause don’t have so much oestrogen any more. Third, and most powerfully, it is total twaddle.

“Do the math,” the authors urge. Alas, I can’t to do the math – or the maths, as we call it in Britain – as I’m not a statistician. But I’ve consulted people who can, and they say it is far from clear that companies with lots of senior women outperform. To prove this, you would need a huge sample – which at the moment does not exist. You would need to adjust for sector and for a thousand other things that influence profitability. And even if you could establish such a link, the case would still not be made, as it might well be that the sort of companies that promote women may also be the sort that treat all employees nicely. Or the sort that are more innovative, and these things might have a greater effect on profitability than oestrogen.

This doesn’t mean I’m not in favour of having women in senior positions. Women make up half the population, and it seems a shame to have them so unrepresented at the top of companies.

Another thing I’m even more strongly in favour of, though, is talking about these things honestly. The senior women at the dinner the other night were all true believers and, therefore, not open to discussion. When I dared to suggest that being female had been massively to my advantage (I wouldn’t be on the board in a million years if I was a man), they looked as if they had sucked on a lemon.

In the interests of openness, last week I e-mailed fellow board members asking them what they thought. Did the other female board member and I add anything by dint of our gender, and if so, what?

She and I had discussed the question in advance and agreed that we thought differently from the men – though, that was more to do with our backgrounds than our sex. Apart from that, we decided that our only oestrogen contribution was to make board dinners a little perkier.

The male directors, by contrast, seemed to set slightly more store by our femaleness. Some said that there might be some (small) motivational effect on the female staff from seeing women on the board and that it might also be (marginally) good for external PR. Others thought we approached board discussions in a slightly different way, and that this was a good thing.

A couple remarked that the board discussion was a bit more polite, and that any tendency towards testosterone-fuelled aggression was slightly tempered. And that, yes, board dinners were better than in the days when there were just eight stale males around the table.

In the same week, I addressed a group of young women managers in a largely male company and asked them some direct questions, too. Did they feel they needed senior women role models? No. Did they feel they could advance if they wanted to? Yes. Did they think it was really hard being a woman? Certainly not.

Yet the thing that interested me most was that these young women freely admitted that they enjoyed using their femininity as a weapon. They viewed flirting not as a sign of weakness but one of strength.

This struck me as thrilling leap forward. When I joined the workforce, we felt that it was a sin against women to flirt, and that we all had to be the same as men. But now I wonder whether this is the very beginning of a brave new post-PC world.

Looking back at the e-mails that some of the male directors sent me, I see one talked about “birds on boards” – which a few years ago I might have drearily forced myself to disapprove of. Now I simply laugh.

This surely is what we should have gained after decades of discussing this issue: enough confidence to go post-PC and not to feel we have to over-egg the argument with dodgy statistics or ludicrous claims about how marvellous women are.

Womenomics, which is stuffed with such claims, does say one thing that made a lot of sense to me last week: "We've never been hotter."

As I toiled my way back from a board meeting last Thursday, the temperature in the London Underground hit 45 degrees celsius.– (Copyright The Financial Times Limited 2009)