I'M an advocate of positive discrimination and using all possible tools to get more women into politics.

So why do I feel uneasy about the call for the major parties to field female candidates in the Dunfermline by-election?

Susan Dalgety (a former ministerial adviser to Jack McConnell) and independence campaigner Kate Higgins have triggered a wave of debate by suggesting this might be the best response to the scandal of the constituency's former MSP Bill Walker, who has been convicted of domestic abuse.

"This month," write Dalgety and Higgins, "Scotland's two political main political parties - the SNP and Scottish Labour - have the chance to send a powerful message about the scourge of domestic abuse, while at the same time making a strong statement about the place of women in our society." Putting forward female candidates would, they say, "signal that our main political parties are determined to secure gender justice and forge a political system at Holyrood that resembles real life, not the back room of a rugby club".

Many agreed. Labour's Michael Marra even dropped his plans for selection, saying the candidate "should be a woman".

But there is something troubling about the equation being made here. A connection has been forged between the Bill Walker scandal and the need for an all-woman shortlist or, at least, the selection of female candidates. One man has done something ugly and ­abhorrent to women, been found guilty and then ultimately been forced by the "media onslaught" to resign in disgrace. And the way we seek to plaster over this horrible gash, and calm the public sense of outrage that such a man should have been put forward as a candidate and tolerated, is to say: No men here - only a woman will do.

Surely this belittles both issues: the question of how we tackle domestic abuse in this country, and also how we get more women into a Parliament whose female representation has slipped from 40% to 34.8%. The problems are indeed linked, both being questions of what Dalgety describes as "gender justice". But there's a danger, when we start connecting them, that we make over-simplifications such as equating men with domestic violence, or women with victimhood. These notions sit on shaky ground. Domestic violence, after all, is not always against women. As Dalgety and Higgins state, women are the victims in eight out of 10 cases, which means one-fifth of domestic abuse victims are men.

Of course, this by-election is not solely about the issue of domestic abuse. But were we to exclude men from standing, we would be making it so. We would also in some way be saying that men are excluded from involvement in the battle against domestic abuse. They have no right to speak, we are implying, since they too are complicit by being men. Yet as with many issues associated with feminism, we need more men involved, not fewer. We need more campaigns like White Ribbon Scotland, which acknowledge that men play a crucial determining role in defining a culture that keeps quiet and tolerates such behaviour, or even encourages it. And we need fewer men stepping back and saying this is a woman's issue.

It is, of course, possible to see Bill Walker as somehow symbolic of a whole culture in which women are more likely to be subject to violence, less likely to be in power, more likely to be living in poverty, and so on. But the important and enduring issue of how to address the gender imbalance on our representative bodies should be debated on its own. It should not require a disgraced male politician to give weight to it.

What we need is a systematic addressing of the ­imbalance, an embracing by the parties of the more general idea of positive ­discrimination. Sadly, the Dunfermline proposal seems like a numbers game, where we eliminate those statistically most likely to be abusers and replace them with women, who are statistically more likely to be abused. This does nothing to enhance our sense that women are the right people for the job. Rather, it enhances the feeling that we need women in there to deal with women's business.

But in spite of all this, I applaud Dalgety and Higgins's opportunism. Whatever happens in this by-election, they have sparked a debate about positive discrimination, and the merits of all-woman shortlists more generally. This issue is being worked through online, on Twitter, as well as on radio phone-in shows. Many of the callers to BBC Radio Scotland's Call Kaye reflected the complacency of our culture, suggesting that if women are not in positions of power, it must simply be because they are not good enough.

All-woman shortlists may not be a perfect tool, but they are probably the best we've got. Without them, it has been estimated, change will be excruciatingly slow. The Fawcett Society not long ago ­calculated that it would take Labour 20 years to get to 50% female candidates, the LibDems 40 years and the Tories 400.

I can think of nothing more depressing, if I were a Dunfermline constituency member, than to see, post-Bill Walker, another line-up of white men fielded for election. But I would not like to see a row of women there as a plaster to the wound left by Walker. I don't think that furthers the case for positive discrimination. Rather it seems like the pressing of a panic button; a yelp of horror. Were it to turn out that this is not a single gesture, but a beginning of a move towards all-woman shortlists, then it should be celebrated.

But my worry is that it appears merely symbolic and reactive. It seems not ­intentional, but fearful and defensive.