Pope Benedict XVI has stressed the Catholic church's opposition to abortion and stem cell research in his first meeting with US president Barack Obama.
The Pope pressed the Vatican's case with Mr Obama, who is already under fire from some conservative Catholics and bishops in the US.
The 30-minute meeting was described by both sides as positive.
The two men agree on helping the poor and pushing for Middle East peace, but disagree on what the Vatican considers prime ethical issues.
"It's a great honour," Mr Obama said, greeting the Pope and thanking him for this first meeting.
The Vatican said the leaders discussed immigration, the Middle East peace process and aid to developing nations. But the Vatican also underscored the pair's deep disagreement on abortion.
"In the course of their cordial exchanges, the conversation turned first of all to questions which are in the interest of all and which constitute a great challenge ... such as the defence and promotion of life and the right to abide by one's conscience," a Vatican statement said.
Even in his gift to the US leader, the Pope sought to underscore his beliefs. Benedict gave Mr Obama a copy of a Vatican document on bioethics that hardened the church's opposition to using embryos for stem cell research, cloning and in-vitro fertilisation. Mr Obama supports stem cell research.
"Yes, this is what we had talked about," Mr Obama said, telling the Pope he would read it on the flight to his next stop, Ghana.
Earlier, the Pope's secretary, the Rev Georg Ganswein, told reporters the document would "help the president better understand the position of the Catholic church".
