What is the Catholic Holy Childhood?

Answer 1

The Association of the Holy Childhood is a fraternity for children (and adults) to try and save children in the missions. You can read about it at the links below:

from The Catholic Encyclopedia:

A children's association for the benefit of foreign missions. Twenty years after the foundation of the Society for the Propagation of the Faith (1843) Charles de Forbin-Janson, Bishop of Nancy, France, established the Society of the Holy Childhood (Association de la Sainte Enfance). Its end is twofold: First, to rally around the Infant Jesus our little Christian children from their tender years, so that with increasing age and strength, and in imitation of Jesus their Master, they may practise true Christian charity with a view to their own perfection; second, that by the practice of charity and enduring liberality those same little Christian children may co-operate in saving from death and sin the many thousands of children that in pagan countries like China are neglected by their parents and cast away to die unbaptized. The further object of the association is to procure baptism for those abandoned little ones, and, should they live, to make of them craftsmen, teachers, doctors, or priests, who in turn will spread the blessings of the Christian religion amongst their countrymen.