When the Norwegian parliament finally decided to make gender quotas mandatory for the boards of publicly listed companies in November 2003, it came as no big surprise. After all, Norway has gender quotas everywhere, from children's councils in schools up to government ministers. The surprise was that the person who championed the mandatory quotas was a male minister from our Conservative party. Ansgar Gabrielsen, then minister of business, told the newspaper Verdens Gang that he was "fed up with the male dominance in the Norwegian boardrooms".

Gabrielsen caught his own party off guard. And soon Conservative MPs who'd habitually quote Ayn Rand and mock the nanny state found themselves forced to vote in favour of a law that gave Norwegian companies about two years to get the percentage of women in the boards of directors up from 7% to 40%. If they didn't reach that goal in time, the state would make the quotas mandatory.

Some supporters of the law hailed the blessings of more diversity in the boardrooms and equal opportunities for the sexes. But Gabrielsen's main argument was that "the boards cannot afford to use only half of the population's brain power". That women actually had some brain power worth using, he tried to show by referring to a survey showing that "everything else" being equal, companies with more women in their boards were more profitable.

Both the NHO, the main employers' organisation, and a couple of high profile male and female business leaders, warned the politicians against the change, claiming that mandatory quotas would depress the value of Norwegian stocks and make women second rate members of the boards. In general most of them agreed that more women on the boards were a good thing. They just thought mandatory quotas were too drastic a measure. Like Winnie the Pooh, bumping his head while being dragged down a flight of stairs and thinking there must be a more comfortable way of getting from A to B, the critics of mandatory quotas thought there must be a more comfortable way to gender balance than threatening the companies that they would be dissolved by court. The Norwegian experience shows it isn't so. The period of voluntary recruitment of women didn't change much. But three years after the law was established, Gabrielsen had his 40%.

Was it worth it? When it comes to diversity, I am not so sure. Most of the female board members are lawyers, economists, and rich heiresses, just like the men they replaced. But at least a survey in 2010 showed that the female members of the boards had a bit more education than their male counterparts.

It's also difficult to show that the females made the companies more profitable. The aforementioned survey might just as well reflect that the companies that hired females voluntarily were more profitable because they were more open-minded than the others. Or, more likely, they had a more professional way of recruiting their members, not just picking their friends. One survey, which was conducted before the law was created, showed that female members of the boards were usually recruited through professional networks, while male members were more commonly recruited through private networks.

The story of the former Norwegian prime minister Gro Harlem Brundtland illustrates the same point. She claimed her career began because of gender quota. Back in the mid-1970s, the then prime minister hadn't made her a minister if it wasn't for the (unofficial) rule that the government had to contain at least one woman. Because of this, Bruntland went into full-time politics. First as a minister, then prime minster, then as leader of the UN committee that came up with the notion of sustainable development. She recently resigned as head of the World Health Organisation.

The same argument goes for boards. The quotas force the companies to look around for women and find talent they wouldn't have found without it.

In non-public companies, the number of women is still far below 40% – and there is no branch of industry where the rate of women is higher than the mandatory 40%. If not forced to by law, companies don't recruit women. In 2003, a Norwegian newspaper discovered that a company owned in part by business minister Gabrielsen had no women on the board at all. As the company wasn't publicly listed, this was all perfectly legal, and yet a little odd for an owner that had spent the last year talking non-stop about the importance of using the brain power of the whole population.

Like the prime minister in the 70s, the business leaders of today have nothing against women. It just so happens that they know so many nice and able men. So why look any further when you are to fill up your board?

Mandatory quotas are bureaucratic, they hurt both the pride of women and the freedom of business. But if you genuinely want more women in the boards, it's probably the only way to achieve it.