VATICAN CITY, JULY 2, 2001 ( The transplanting of animal organs to people must respect three fundamental criteria, John Paul II said in a message published today by the Vatican.

Given the "new problems of a scientific and ethical nature" posed by these transplants, the Pope said the procedures have "to be concerned, at the same time, with the good and dignity of the human person; the possible risks to health, which cannot always be quantified or foreseen; and respect for animals, which is always necessary, even when they are operated on for the higher good of man."

The guidelines came in a message addressed to a group of anthropologists, geneticists and moralists meeting in the Vatican today with Bishop Elio Sgreccia.

They are participating in a congress organized by the Pontifical Academy for Life on the justness of "xenotransplants," as they are called scientifically.

The transplant of animal organs to humans is vital, the Pope explains, because it could help to "resolve the problem of the grave insufficiency of valid human organs for transplants." Many patients die while waiting for a donor organ.

In face of this challenge, the Holy Father proposes two alliances for the progress of scientific research.

First, John Paul II highlights cooperation between science and ethics, because increasingly it is "more clearly seen" that this alliance "enriches the two branches of learning and invites them to converge when it comes to lending their help to every man and to society."

Second, the Pope proposes an alliance between faith and science, because "rational reflection, confirmed by faith, discovers that God the creator has placed man at the summit of the visible world and, at the same time, entrusted him with the task of directing his own way, by respecting his own dignity, and pursuing the genuine good of his fellowmen."

He concludes: "Therefore, the Church will always give her support and aid to anyone seeking the authentic good of man, with the effort of reason, illuminated by faith."