Pope Benedict XVI on Monday appealed for the respect of the "dignity of children" during Midnight Mass attended by thousands at St Peter's Basilica and watched by millions more on television.
With the birth of Jesus in a stable in Bethlehem, God "teaches us respect for children," the pope said in his homily broadcast live on 73 television stations in 47 countries.
"The child of Bethlehem directs our gaze towards all children who suffer and are abused in the world, the born and the unborn," said the spiritual leader of the world's 1.1 billion Catholics.
Speaking in Italian, he pointed to "children who are placed as soldiers in a violent world ... children who have to beg ... children who suffer deprivation and hunger ... children who are unloved."
He said: "In all of these it is the child of Bethlehem who is crying out to us. ... Let us pray this night that the brightness of God's love may enfold all these children. Let us ask God to help us do our part so that the dignity of children may be respected."
Benedict, celebrating his second Midnight Mass since his election in April 2005, then spoke of Christmas as a "feast of gifts in imitation of God who has given himself to us."
He said: "Among the many gifts that we buy and receive, let us not forget the true gift: to give each other something of ourselves."
The mass in Latin, the universal language of the Roman Catholic Church, was punctuated by readings in Italian, English, French, German, Spanish and Polish. The traditional prayers of the faithful were done in Portuguese, Arabic and the Philippine language Tagalog.
At noon on Monday, the pope was to pronounce the traditional Urbi et Orbi (to the city and the world) message from the balcony of Saint Peter's, to an even greater audience watching 102 television stations in 63 countries.
On Sunday the pope used his pre-Christmas Angelus blessing to underline the "value of every human life" amid controversy over the death of Italian right-to-die campaigner Piergiorgio Welby.
"The birth of Christ helps us to be aware of what human life is worth, the value of every human life, from his first moment to his natural decline," the pope said.
Welby, who died on Wednesday, had a civil funeral in Rome on Sunday after Italy's Roman Catholic Church refused religious rites for the muscular dystrophy victim.
Welby's activism has sparked a debate on euthanasia in overwhelmingly Roman Catholic Italy, where it is punishable by up to 15 years in prison, although patients are legally allowed to refuse care.