In his latest blunt assessment of U.S. society, Pope John Paul II (search) on Friday denounced the acceptance of abortion and same-sex unions (search) as "self-centered demands" erroneously depicted as human rights.

The pontiff said that "in the face of such erroneous yet pervasive thinking," visiting U.S. bishops should stress to congregations "their special responsibility for evangelizing culture and promoting Christian values in society and public life."

"Rights are at times reduced to self-centered demands: the growth of prostitution and pornography in the name of adult choice, the acceptance of abortion in the name of women's rights, the approval of same sex unions in the name of homosexual rights," he said.

The Catholic Church (search) forbids abortion and considers homosexual activity a sin.

Last week, John Paul warned another group of U.S. prelates that American society is in danger of surrendering to a "soulless vision of life."

Greeting the latest group of bishops on the same day he held a private audience with President Bush, John Paul acknowledged the challenges to Catholic Church teaching and faith.

"Ambiguous moral positions, the distortion of reason by particular interest groups ... are just some examples of a perspective of life which fails to seek truth itself and then abandons the search for the ultimate goal and meaning of human existence," John Paul said.

He urged church leaders to be courageous despite detractors. "Some today view Christianity as weighed down by structures and failing to respond to people's spiritual needs," he said.

Every bishop must visit the Vatican every five years for periodic consultations. This year is the turn of bishops from the United States.