As international migration has more than doubled in the past four decades, women migrants can find an empowering experience in improving their social roles, even though they also face many risks, including gender violence and trafficking, a report to the United Nations General Assembly from Secretary-General Kofi Annan says.
"Gender inequality can be a powerful factor in precipitating migration when women have economic, political and social expectation that opportunities at home do not meet," says the report, "World Survey on the Role of Women in Development."
"In the process of international migration women may move away from situations where they live under traditional, patriarchal authority to situations where they are empowered to exercise greater autonomy over their own lives.
"A gender perspective is essential to understanding both the causes and consequences of international migration," the report adds.
Even women who remain in their countries when husbands or children migrate may find themselves taking on new, decision-making roles and responsibilities, it says.
And though they generally earn less than men, voluntary migrant women send home remittances which help their countries of origin to develop and they may influence the national attitudes to women's rights and opportunities.
The report, which updates previous surveys, responds to Assembly requests in 1999 and 2003. It notes, however, "the dearth of data" on women and migration. Statistics on migrants are often published without breaking them down by gender and age.
The number of international migrants has risen to about 175 million in 2000, or 2.9 per cent of the world's population, from about 75 million, or 2.5 per cent of the world's population, in 1960. The proportion of women migrants during the same period rose to 49 per cent, from 46.6 per cent.
Meanwhile, the recipient country may have laws discriminating against migrant women, such as giving them pregnancy tests, making it harder or impossible for their husbands and children to join them, requiring permission from a guardian, or imposing age limits.
Worse, women may believe that they have legitimate jobs in the new country, only to find that they have been trapped into prostitution, sweatshop work or what are considered other contemporary forms of slavery.
"The trafficking of people for prostitution and forced labour is one of the fastest-growing areas of international criminal activity and one that is of increasing concern to the international community," it says.