Unreconstructed attitudes to women are restricting economic growth in the Middle East and North Africa, the World Bank has warned.
Tradition is only part of the story
"No country can raise the standard of living and improve the well-being of its people without the participation of half its population," said Christiaan Portman, the Bank's chief for the region.
Improvements in women's welfare and freedom have paid dividends in many countries, the Bank said - but it insisted that there was still a huge distance to travel.
Even counting relatively liberal countries such as Egypt, less than one-third of women regionwide are in the workforce, roughly half the global average.
There is a mismatch, the World Bank said, between women's expectations and their achievements.
Most Middle Eastern countries have hugely expanded their investments in women's education, producing a remarkable improvement in attainment.
Female literacy, for example, has risen from 17% regionwide in 1970 to 53% in 2000.
But the involvement of women in the economy has not increased in step with education.
""By investing in women's education, [Middle Eastern and North African] countries have increased aspirations and ability to earn incomes," said Mustapha Nabli, the Bank chief economist for the region.
"But the low levels of female participation in the labour force mean the region is not reaping the returns of this investment."
Part of the exclusion reflects conservative attitudes; many men in the region still fear losing their jobs if women join the workforce in greater numbers.
And in many countries, men are seen as the only natural breadwinners - a role often reinforced by legislation or tax rules.
Educational attainment has not always paid off
But low female participation is also related to women's established preference for public-sector jobs, such as medicine, teaching or the civil service - a sector of the economy that is shrinking fast all over the region.
As a result, for every working person in the region there are two non-earning dependents - a figure twice the level seen in Asia, for example.
Focusing in on a few countries in the region, the World Bank calculates that growth in output per head could have been 0.7 percentage points brisker if women had played a full economic part.
That sort of increase could have made a genuine difference, given that regional per-capita production growth has been less than 2% per year in recent decades.
The World Bank study is the latest in a series of reports from it and its sister organisation, the International Monetary Fund, on economic problems in the region.
The two agencies are holding their joint annual meetings in Dubai this week, and are keen to explore reasons for the historically poor performance of the region's economies.
Below-par economic growth, some analysts have argued, contributes to Middle Eastern political instability, and helps foster the sort of atmosphere within which terrorist groups can thrive.