Pope Benedict XVI on Friday urged doctors to develop more accurate methods of determining brain death in vital organ donors.
Speaking to a conference on transplants organised by the Pontifical Academy for Life and the International Federation of Catholic Medical Associations, Benedict said advances were necessary so that there would not be even ''the smallest suspicion of doubt'' over whether a donor is brain dead before organs are removed.
In cases of non-vital organ donation, the donor must ''never be placed in serious danger for his own health,'' the pope added.
He described scientific advances in transplants as ''a great conquest in medical science'', but warned that ''market logic'' should not be used to address the now ''dramatic'' problem of patients waiting for available organs.
Selling organs is ''morally wrong'' and ''to be condemned as abominable'', Benedict said.
The pope stressed that organ donation should be free and voluntary, describing it as ''a special form...of charity''.
The scientific community agreed on a definition of brain death with an influential report 40 years ago that was also approved by the Catholic Church, but there have been calls from Catholics to revisit the issue.
Most recently, Vatican daily Osservatore Romano in September published an article saying that while the Catholic Church had agreed with the accepted definition in the past, new evidence indicated ''brain death is not the death of a human being''.
The pope himself registered with an organ donor association while still a cardinal, saying in a statement issued at the time that he always carried his card with him giving his consent to organ transplants in case of death.
In September the association said membership implies that the eventual donor agrees with the accepted definition of brain death.
It stressed that the decision had been made by Benedict when not yet pope.
