The gender gap in pay is highlighted by Cathy Arnst in her BusinessWeek blog. "One year out of college, women working full time earn 80% percent of what men earn. Ten years later, women earn 69% percent as much as men."

So what's the solution? One provocative answer comes from two academics, Alberto Alesina from Harvard and Andrea Ichino from the University of Bologna. They've produced a thought-provoking piece in the Financial Times Why Women Should Pay Less Tax.

The piece, republished in full here, argues that we need to reduce income taxes on women, and increase taxes on men.

"The supply of labour of women is more responsive to their after-tax wage, so a reduction in taxes increases the labour participation of women substantially. Men's labour supply is more rigid, so an increase in taxes does not reduce their labour supply by much, if at all. Ergo, for a given tax cut on women, with a smaller tax increase on men, one maintains the same total revenue with fewer tax distortions. This is simply an application of the general principle of public finance that goods with a more elastic supply should be taxed less ... There is nothing more hypocritical than to invoke equal treatment in some areas (taxation) for those who are not treated equally in many other areas (the labour market; sometimes in the family allocation of tasks, such as rearing children or caring for elder family members). We already have a host of policies that are not gender neutral. We could eliminate many of them by adopting a simple differentiation of tax schedules for men and women. And do not forget that a large part of the redistribution of the tax burden implied by this proposal would occur within the same family: the husbands of married women who choose to work would also benefit from their wife earning a higher take-home salary."

You can read their research paper here.

The Economist makes the excellent point that getting more women into the workforce would help deal with the problems of an ageing society.

But is gender-based tax discrimination the way to go? How would it deal, for example, with single fathers? And how does it address the fact that many women when they return to the workforce, go back part-time? Would they really go full time if you gave them a tax cut?

Then there are the other problems highlighted in the Relentlessly Progressive Political Economy blog.

"Further, the overall notion that women have a more elastic labour supply is problematic as it disregards class. How many poor women, a group that is disproportionately working, can increase labour hours in response to higher wages? The authors also believe women's new found higher incomes will allow their families to purchase child care at market prices, which makes me wonder if the authors know how much unsubsidized day care costs. Poor to middle class families struggle to fund childcare, and it's not a matter of an extra couple hundred bucks a month."

Women's pay gap can't be fixed by adjusting the tax rate. There are some more basic and obvious solutions.