Twenty years ago the United Nations adopted the Convention of the Rights of the Child. The CRC or UNCRC, is an international treaty setting out the civil, political, economic, social and cultural rights of children.
Nations that ratify the UNCRC are bound to it by international law.
As of December 2008, 193 signatories have ratified it, including every member of the United Nations except the US and Somalia.
The UNCRC has been used as a blueprint for child protection legislation around the world
The treaty restricts the involvement of children in military conflicts and prohibits the sale of children, child prostitution and child pornography.
Bangladesh is a signatory to the UN pact.
However, child marriage remains a widely accepted practice.
According to a UN report, 63 per cent of all Bangladeshi girls below the age of 25 are married off before they reach the legal age of 18.
Non-governmental organisations in the country are trying implement a clause in the UNCRC to protect underage brides.
Al Jazeera's Nicolas Haque reports from Dhaka on how the simple birth certificate can help reduce the number of children forced into marriages.
The extreme cases of child marriages also include the Democratic Republic of Congo and Afghanistan.