The latest U.N. report on education says girls face sharp discrimination in access to education, which means millions of them are kept out of school. The report says the lack of gender parity in education is an important obstacle to social and economic progress. The report was introduced Thursday in New Delhi.

In many developing countries, particularly in South Asia and sub-Saharan Africa, there are only seven girls in primary school for every 10 boys. In the world's two most populous countries, India and China, boys continue to outnumber girls in schools.

The annual Education for All report by UNESCO says the proportion of girls in school did rise slightly in the past decade. But more than half of the 104 million children out of school are still females, making gender parity in education a distant goal in more than 50 countries.

The U.N. says that in many countries, high school fees, early marriage, and economic pressure to put children to work early block girls from school.

Christopher Colclough, the Paris-based director for the Education for All report, is calling for a change in the cultural and social values that keep girls out of school, particularly in poor countries.

"The poor countries in the world tend to be the ones in which the social norms and values of society are most tolerant of inequality, and where the roles of men and women in society are more sharply different," he said. "Parents give different opportunities and different resources to boys and girls stemming from those different values."

The United Nations is calling for countries to make primary education free, and reduce the dependence of poor households on child labor to ensure that more girls get into school. It says educating girls has a high payoff by increasing household incomes and reducing poverty.

Mr. Colclough also is asking countries to adopt innovative methods to help girls stay in school. He cites the example of one of the world's poorest countries, Bangladesh, where several programs have helped tens-of-thousands of poor girls reach secondary school.

"It is done this both by very imaginative approaches to school expansion, which have emphasized the role of women teachers, emphasized flexibility in terms of the school timetable, and also done it by introduction of scholarships ? which have been focused on the poor," he said.

The report also expresses concern that during the 1990s more than 100,000 girls directly participated in conflicts in at least 30 countries as fighters, cooks, spies, servants, and sex slaves.