International Adoption: The Human Rights Position is an article in Global Policy by Harvard Law Professor Elizabeth Bartholet. A response article from Paulo Barrozo of Boston College Law School amplifies some of her points.
In brief: UNICEF has been at the forefront of pressuring national governments to set up so many hurdles as to make international adoption rare and extremely time-consuming. The result is that children languish in miserable, hellish orphanages for years. During the critical early months and years in which interaction with loving parents is essential to a child's normal brain development, the children are neglected and left in squalor.
According to Bartholet, all this is a violation of international treaties about the rights of children, which one might expect UNICEF, of all entities, to be especially scrupulous about obeying. Besides, you don't need to be an international lawyer to see the flaws of policy that leaves children in terrible orphanages, or as menial servants and de facto slaves in "the community," rather than in loving homes.
In a 2007 article, I discussed UNICEF's record in propagandizing for Palestinian terrorism, and its collaboration with the North Korean dictatorship and with the Saddam Hussein regime.
So in short, if you want to give to a charity which does not spend any money on harming children, UNICEF is a poor choice.
It's that time of year when giving to a charity is a most thoughtful and meaningful thing to do. Might I suggest passing up on giving anything to UNICEF and perhaps giving to these folks (click on the image):