"The quality of social and civil life and the quality of democracy depend in large measure" on all citizens possessing and exercising a conscience that listens, not to subjective feelings, but to an objective truth that recognizes one's duty to God and all human beings, he said.

Such moral consciences are formed in Christian families, parishes and Catholic schools, the Pope said.

"This logic of gratuitousness, learned in infancy and adolescence, is then lived out in every area of life, in games, in sport, in interpersonal relations, in art, in voluntary service to the poor and suffering," as well as in policy making and the economy, he said.

The 84-year-old Pope headed to the Croatian capital in an effort to encourage this predominantly Catholic country to resist secular temptations and hold strong to its Christian identity as it prepares for full integration into the European Union. It was Pope Benedict's 19th trip outside Italy and 13th to a European nation.

Even though nearly 90 per cent of the country's population declare themselves Catholic, the bishops say the country is experiencing fierce pressure to allow adoptions by same-sex couples, ease restrictions on artificial reproduction and legalize euthanasia. Divorce and abortion are legal and same-sex civil partnerships are recognized in Croatia.

Before hundreds of thousands of families and young people gathered for Mass in Zagrab's grassy hippodrome June 5, Bishop Valter Zupan of Krk, Croatia, decried current threats against the family saying alternative lifestyles "have no basis in European culture" and every child has the right to have both a mother and a father.

The bishop, president of the Croatian bishops' commission for the family, urged the government to defend life by reconsidering its abortion laws and to stop calling something "that leads to death, progress."

The emphasis on the family came as part of the country's first national gathering of Croatian families. Some 400,000 people attended, including families, bishops, priests and religious from nearby nations including Slovenia, Serbia, Albania and Macedonia.

Jubilant crowds squelched through the muddy fields to chase after the popemobile as it slowly circled the giant horse track. People waved banners and Vatican and Croatian flags and many babies braved being passed over barricades and through the open popemobile window to receive a kiss and blessing from the Pope.

In his homily, Pope Benedict called on the government to support families and he urged young men and women to be courageous and fend off trends that advocate "living together as a preparation, or even a substitute for marriage."

"The presence of exemplary Christian families is more necessary and urgent than ever" in a world that promotes false freedoms, materialism, superficial relationships and an empty, sentimental notion of love that seeks "the gratification of instinctive impulses without a commitment to build lasting bonds," he said.

"Do not be afraid to make a commitment to another person," he said as he encouraged married couples to be open to life since the "respect for natural moral law frees people, rather than demeaning them."

In an evening vespers service in the neo-Gothic Zagreb Cathedral June 5, the Pope urged bishops to be vigilant and guide the faithful to ensure the Church's moral teaching was correctly understood in light of the Gospel. Pope Benedict urged Church leaders "to strive for reconciliation among separated Christians and between Christians and Muslims" in reference to lingering religious and ethnic tensions between Croats, Serbian Orthodox and Muslims that once plagued the Balkan region.

The Pope's trip coincided with Croatia's 20th anniversary of its independence from Yugoslavia and the eve of its full accession into the European Union. Pope Benedict has long supported Croatia's entry into the economic and political bloc of 27 member states.