The Shareholders Association felt the rule should also have included disclosure about ethnicity.
Others, such as high-profile director Joan Withers, were happy with the move and felt it got the balance right in terms of encouraging progress without being too heavy handed.
The issue is divisive across gender lines particularly because many successful businesswomen share libertarian values with their male peers.
They would argue that there is little or no place for regulatory intervention here and companies should be free to pick whoever they feel is best for a job.
Arguments in favour of disclosure rules and quotas quickly run into difficulties if extrapolated to extremes.
What about ethnicity? Would we be okay with a rule that required the disclosure of Jewish people on a board?
What about sexuality? Is that anybody's business - where do we draw the line?
You could argue that what is important is the intent of the rule.
The kind of ethnic disclosure required in Nazi Germany was aimed at undermining the social groups, not promoting them. Essentially, the rules came from a bad place rather than a good one.
That is subjective, of course, but this isn't particle physics. In human endeavours pragmatic solutions are usually more successful than efforts to apply some grand unified theory.
Are there practical reasons for a better gender balance?
Businesswomen presumably have a head start in understanding female customers. It is already the case that retail companies have better female representation than, say, freight and logistics companies or other business-to-business operators.
But while that's the way things are, it's not a state of affairs that stands up to much scrutiny.
In the business-to-business space there are fewer female customers because there are fewer female chief executives and board members so the situation is self perpetuating.
One issue fundamental to the debate is actually recognising that there is a problem to deal with.
First up, is there a gender imbalance? Well clearly yes.
Last decade the public prominence of a few high-profile women - for example Helen Clark and Telecom chief Theresa Gattung - created an impression that New Zealand was somehow ahead of the curve in this area.
It wasn't and still isn't.
Last year women occupied just 9.3 per cent of board seats in New Zealand's largest listed companies.
When the Business Herald did its annual executive pay survey for 2011 it was surprising to discover that there were no female chief executives on the list, which included most of the NZX 50 and several other large companies including state-owned enterprises.
The imbalance is quite stark.
So the next question: is there an inherent need for a gender balance, is it patronising to suggest women need some sort of regulatory intervention or even that women represent some sort of homogenous group?
Two women sitting side by side on a board might have considerably different attitudes and skills. A male and female director around the same table may have a lot more in common.
What unites women as a group beyond their physical genetics, and why is that relevant to business?
Two of our four biggest banks now have female chief executives either locally or at group level - ASB's Barbara Chapman and Westpac's Australian chief Gail Kelly. Neither bank seems more feminine than its competitors.
If boards need diversity, then should we not be looking more closely at skill sets?
It might be more relevant for companies to disclose how many engineers, how many accountants and how many marketing specialists they have on their boards.
Well, actually they already do, in the biographies they supply to shareholders online and in company reports.
And that information generally tends to include the gender of directors and the executive team.
So on a company-by-company basis it is not as if gender information is being hidden from shareholders.
The upshot is that the NZX rule doesn't really change much at all but its creation is still significant.
It is symbolic and it is symbolic of something a lot of people are still not comfortable with.
It implicitly recognises the need for social change.
It is an admission - from the core of our capital markets - that there is a problem to be addressed.
Real change probably needs to come from the ground up - the way we bring up and educate young women, the goals and aspirations we encourage for them. But if you want to build some momentum from the ground up then it can help to send a signal from the top down.
Nearly 120 years since New Zealand led the world in giving women the vote, 40 years since the feminist movement went mainstream, the number of women in the top tier of our business community is an embarrassment.
As a nation we can either do nothing about that or we can do something.
The NZX has decided it is worth doing something.
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