I would suggest that many of the rights are not purely the result of Christian thinking. They are a result of the collected wisdom of mankind and no one religion has a claim to all of this wisdom. UN Rights of the Child were based on the work of Korczak who was a Polish Jew.

Are the following really Christian?
Article 4: No one shall be held in slavery or servitude
Many Christians fought against slavery (mainly non-Conformists from what I understand), but the Church was also complicit in these crimes for generations. Some of the most ardent anti-abolitionists were good Christian people.

Article 5: No one shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment
Not exactly a principle accepted by the Spanish Inquisition or in dealing with Anabaptists in Munster (just a couple of examples).

Article 20: Everyone has the right to freedom of peaceful assembly and association.
The Catholic church was banned in England until the 19th Century.

UN Declaration of Human Rights were a product of more than just Christianity, but it is noticable that it does not recognise Sexual preference as a human right. I suspect without the power of the church this form of equality would have been included.