(...) Incredibly, until a decade ago, it was legal under international law to recruit children as young as Aruna and send them into combat. That changed 10 years ago on February 12, 2002, when a new United Nations treaty took effect, setting 18 as the minimum age for conscription or direct participation in armed conflict.
Thousands of children are still participating in armed conflicts. As a human rights researcher, I’ve heard dozens of their stories in countries like Sri Lanka, Uganda, and Burma. But what is less-well-known is the remarkable progress made in ending the use of child soldiers.
Two-thirds of the world’s countries have signed onto the UN treaty, prompting a seismic shift in how government and military leaders address the use of child soldiers. While the treaty was being negotiated in the late 1990s, I heard diplomats rationalizing the use of children by military forces. The US, too, initially opposed the treaty. But today, virtually no one defends the practice. (...)

The article:
http://www.hrw.org/news/2012/02/13/getting-children-battlefield

Basic information:
http://en.wikipedia.org/wiki/Military_use_of_children
http://it.wikipedia.org/wiki/Bambini_soldato

More about:

http://www.un.org/apps/news/story.asp?NewsID=42849&Cr=children+and+armed+conflict&Cr1=#.UFC6GFF1jCY

Passato...prossimo:
http://www.fabiomanzione.it/index.php?option=com_content&view=article&id=2408:bambini-soldato-24-paesi-continuano-a-usare-minori-armati-nei-conflitti&catid=46:diritti-umani&Itemid=105