Human rights group Equality Now says more than 140 million girls over the next decade will be married before they turn 18.
Cultural traditions and a lack of legal protections are driving tens of millions of girls around the world into early marriage, subjecting them to violence, poverty and mistreatment, an international human rights group says.
Equality Now, citing the United Nations Population Fund, said in a report issued over the weekend that more than 140 million girls over the next decade will be married before they turn 18.
"When a young girl is married and gives birth, the vicious cycle of poverty, poor health, curtailed education, violence, instability, disregard for rule of law ... continues into the next generation, especially for any daughters she may have," the report said.
The 32-page report found that despite laws that set a minimum age for marriage in many countries, social norms continue to provide a veneer of legitimacy to child marriage in remote villages and even in developed countries. Child marriage is defined as a marriage before age 18.
"Child marriage legitimises human rights violations and abuses of girls under the guise of culture, honour, tradition and religion," the report said.
The report gave examples of cases in countries such as Afghanistan, Cameroon, Guatemala, India, Jordan, Kenya, Malawi and Mali.
Often when child brides are married off to older men, it is to restore or maintain family honour, or to settle a father's debts or obtain some other financial gain. A girl married off is seen as one less mouth to feed, and the wedding dowry is spent by her family to support itself.
In some countries, families encourage early marriage to protect young girls from premarital sex and to uphold a family's honour, according to the report.
In one case, a young girl named Mariam was born in France to parents from Mali. She had never been to Mali until her father sent her at age 14 and her sister at 16 to a village while they were on vacation from school.
When they arrived, their father took their passports, and Mariam was told to marry her father's cousin. Her sister was to marry the local imam, or preacher. Mariam eventually escaped with the help of a policeman she met during a visit to the village market, but her sister remains in Mali, the report said.
Equality Now said it uses pseudonyms for girls for their safety.
In another case in Afghanistan, a 3-year-old girl's father killed a man. To avoid prison, he handed his daughter over to the victim's family, which regularly beat her and forced her to do household chores. At 10 she was raped by an older man in the family, and that same year she was married to a teenager from the family.
Her husband divorced her when she was 12, and she was forced to marry the uncle who had raped her. It was not until she managed to run away that police helped her find shelter with a women's organisation. The uncle was arrested and is serving a 13-year sentence for rape, Equality Now said.
Equality Now said child marriages often lead to young brides who are isolated and, because of their marital status, have little access to education and other services generally provided to children. In cases where a girl has the legal right to void her marriage, it is difficult to do so without knowledge of the law, education and financial support.
The UN population fund says rates of child marriage are highest in the West African nation of Niger, where 75 per cent of girls are married before they turn 18, and a third are wed before age 15. Under Niger's law, the minimum age for marriage is 15, but traditional customs often prevail in villages.
In Bangladesh, the rate of child marriage is 66 per cent, and in Central African Republic and Chad it is 68 per cent. In India, 47 per cent of girls are married before they turn 18.
In the Middle East, Saudi Arabia and Yemen are the only Arab countries that do not have laws that set a minimum age for marriage. According to a December 2011 Human Rights Watch report, approximately 14 per cent of girls in Yemen, the Arab world's poorest nation, were married before age 15, and 52 per cent were wed before they turned 18.