'The idea that international NGOs can come up with one standard for best practise in every part of the world, with vastly different conditions and lifestyles, seem unlikely on the face of it'
Children/ young people are children/ young people wherever they are.
This is cultural relativism I think?
It makes no odds to us really. Showing support for the efforts to reduce/ prevent child marriage overseas is a good thing to do.
There still is child marriage in the USA btw it's not restricted to one continent or region.