It's part of a broader spectrum effort by the UN, by their
UNICEF wing, to improve conditions for children worldwide.
[1]
http://www.unicef.org/crc/ I'm embarrassed at my own country
(USA) that we have not accepted the United National Declaration
on the Rights of a Child. We allow working conditions and things
like underage marriage and many other violations to continue.
We're accustomed to them. For example, children are allowed to
work in family restaurants, doing tasks forbidden in many other
countries. We see it as empowerment but from the UN's eyes, its
seen as exploitation. The thing is: It probably _is_
exploitation yet because of how we frame it for ourselves, we
can't and won't be able to see it. I suspect it is similar in
the case of child brides. Places where it is traditional and
existing social customs and laws exist to protect them somewhat
are nevertheless falling far short of the UN recommendations.
Poor enforcement of laws are a big reason for it, likely because
the places where many of these things occur are in areas of
poverty, where, just like in the USA, things are allowed to
happen because "poor people don't count". In the US, we disown
them by saying, "They're welfare mothers having kids to get
income" and such, dehumanizing them, making them "not our
problem". Each country commits abuses everyday - one doesn't
have to look for child brides in far off lands - they likely
exist in whatever your country is, because few countries enforce
a strict 18+ only for marriage, as youth liberation movements
often run counter to child protection movements.
References
Visible links
1.
http://l.facebook.com/l.php?u=http%3A%2F%2Fwww.unicef.org%2Fcrc%2F&h=aAQF2VU3r