Pope Benedict XVI has denounced the "disintegration" of family life in Europe and called for couples to make a commitment to marry and have children, not just live together, as he reaffirmed traditional Catholic family values during his second and final day in Croatia.
Benedict also voiced the Vatican's opposition to abortion at an open-air Mass at Zagreb's hippodrome, the highlight of his trip to mark the local church's national day of families.
Tens of thousands of people, waving small plastic Croatian and Vatican flags, began arriving before dawn at the field muddied by overnight thunderstorms.
The sun shone through the clouds as Benedict arrived for the Mass in his white popemobile, waving to the crowd as he looped around the field, which has a capacity of some 300,000 and appeared nearly full with faithful from across Croatia and neighbouring countries.
This is Benedict's first visit as pope to Croatia, an overwhelmingly Catholic Balkan nation that is poised to soon join the European Union. The Vatican has strongly supported its bid, eager to see another country with shared values join the 27-member bloc.
Yet while Croatia is nearly 90% Catholic, it allows some legal rights for same-sex couples and, thanks to leftover communist-era legislation, permits abortion up to 10 weeks after conception and thereafter with the consent of a special commission of doctors.
In his homily, Benedict lamented the "increasing disintegration of the family, especially in Europe" and urged young couples to resist "that secularised mentality which proposes living together as a preparation, or even a substitute for marriage."
"Do not be afraid to make a commitment to another person," he said.
He urged parents to affirm the inviolability of life from conception to natural death - Vatican-speak for opposition to abortion, saying "Dear families, rejoice in fatherhood and motherhood." He also urged them to back legislation that supports families "in the task of giving birth to children and educating them".
His message - delivered mostly in Italian and translated into Croatian - has been received with a resounding welcome in Croatia, which Benedict's predecessor Pope John Paul II visited three times during and after the Balkan wars of the 1990s.