Inequality and unequal access to education holds millions of girls and women back across the world. While the "gender gap" in education has narrowed over the past decade, girls are still at a disadvantage, particularly in getting access to high school education. And women still constitute two-thirds of the world's illiterate population.

This gender gap is generally wider at higher levels of schooling. According to some estimates, women in South Asia, for example, have only half as many years of education as men, and female enrollment rates at the high-school level are two-thirds that of males.

Within countries, gender disparity is greater among the poor, and in some countries the disparity continues among the poor even after they have disappeared among the wealthier sectors of the population. To be a girl from a poor family thus becomes a double disadvantage. In addition, gender bias - approaches to teaching and the degree of attention from teachers - puts girls at a further disadvantage.

Overall access to basic education has risen markedly over the past decade in many developing countries. In spite of that poor children are still less likely to attend school or be enrolled in school and more likely to repeat grades than those who come from wealthier families.

There is widespread agreement that primary school education should become universal early this century, but the differences in educational attendance and attainment according to economic status show that the poor are less likely to achieve this goal than those better off economically.

There are several reasons to explain this gap. It is harder for poor children to have easy access to schools, because schools tend to be concentrated in cities and areas where only better-off families live. Physical availability of schools, though, is not the most critical factor in most developing countries. It is important to consider not only national averages, but also how poor girls in rural areas are faring.

Although expenditures on education have increased over the past few decades in many countries, unless these resources are specifically addressed to those most vulnerable, they will tend to increase disparities rather than decrease them.

Disparities in attaining education have been attributed to ineffective school systems. Governments tend to spend less on public primary and high school education - the type of schooling that tends to benefit the poor most - during economic crises. Wars, civil conflicts, economic disruptions and epidemics alter services and affect school attendance. All these problems are likely to have a greater effect on the poor.

Elimination of gender bias in education is particularly important when the level of education of parents is linked to their children's educational attainment. Several studies have shown that educating mothers is more important than educating fathers to increase the chances of their children's success. In addition, a great deal of evidence shows the benefits of women's schooling not only for their children's to attain education, but also for their health, nutrition and survival. Immunization rates among children of educated mothers, for example, have been consistently higher than those of uneducated mothers.

Educated girls can develop essential life skills, including self-confidence, the ability to participate effectively in society, and the capacity to better protect themselves from HIV/AIDS and sexual exploitation. In addition, several studies have shown that educated women not only have fewer children but also have better economic prospects themselves. Girls' education not only empowers them, but also is considered the best investment in a country's development.

Several factors indicate that special attention must be paid to the poor. Poor women are more likely to die during pregnancy or at childbirth. Increasing expenditure on education for the poorer section of society yields better returns in productivity, income and economic growth. In contrast, inequality in the distribution of education has held down economic growth and per capita income in many countries.

Taking measures to alleviate poverty has become an urgent global priority. And one of the best ways to reduce poverty is to increase the educational level of the poor, particularly the girls among them.

The author is an international public health consultant.