Father Scott Borgman, an official at the Pontifical Academy for Life, told Catholic News Service March 27 that there were not enough sponsors or registrations to be able to cover costs.

"It was just a matter of numbers; we were short thousands of euros to be able to carry this through" and academy staffers had exhausted all efforts over the past three months to find new sources of funding, he said.

The president of the Catholic medical federation, Jose Simon Castellvi, told CNS by email that it was "a pity, but economic problems" and too many Vatican-based conferences on stem cells being scheduled too close together had led to the March 23 cancellation of the congress.

In November, the Pontifical Council for Culture, partnered with NeoStem Inc., a U.S. company researching and marketing adult stem-cell therapies, sponsored a similar conference on adult stem cells with many of the same speakers who were scheduled to attend the late-April event.

And the Pontifical Academy of Sciences was holding a closed-door working group April 16-17 on new developments in stem-cell research.

Three members of the life academy told news outlets they were pleased the conference was canceled because they opposed the attendance of speakers who work with embryonic stem cells and support their use in medical research.

One academy member told CNS "it was opportune to cancel the April planned congress" because it must be shown that research on adult stem cells is "much more promising" than the research coming out of experiments done with embryonic stem cells.

The member, Msgr. Michel Schooyans, a retired professor of theology and philosophy at the Catholic University of Louvain, Belgium, told CNS in an email exchange that he was "not directly part of the group of members of the Pontifical Academy for Life who called for the cancellation."

However, he said members of the academy who were vocally opposed to the inclusion of some experts at the congress were motivated by "their fidelity to the teaching of the Catholic Church about the respect of human life from the beginning to natural death."

The life academy held very successful similar congresses in Rome in 2006 and in Monaco in 2009 with no controversy, Father Borgman said.

The four organizations that sponsor the congresses "are completely faithful to the magisterium. We're not trying to split the Vatican and start a scandal," he said.

The Catholic Church opposes research using human embryonic stem cells, but supports research and therapies utilizing adult stem cells, which have the possibility of developing into a variety of specialized cells and can alleviate degenerative illnesses by repairing damaged tissues.

Like the sciences academy and the culture council's initiatives, the Pontifical Academy for Life understands that some people who do not uphold church teaching can still be able "to contribute to scientific research which is in line with Catholic doctrine," the U.S. priest said.

He said the organizing committee, which was made up of stem-cell scientists, chose speakers who represented the best and brightest in the field of adult stem-cell research and that it did not chose speakers according to their religious affiliation or adherence to church teaching.

All speakers, including those who use or support the use of embryonic stem cells in research, "had agreed to talk about adult stem-cell research" in their presentations, he said.

The church needs to hear from all experts and cannot "make assumptions based on hearsay," he said, as it works to formulate clear guidelines on the ethical use of rapidly changing technologies and new discoveries.

Simon said he was not in favor of having "unorthodox" speakers, but said some scientists are changing their position and no longer support the destruction of embryos.

Msgr. Schooyans said while an exchange of different points of view is laudable, the subject of respecting human life is "non-negotiable."

"The halls of the Holy See should not be put at the disposal of researchers whose positions are in open disagreement with the teaching of the church about life," he said, adding that there was a danger some researchers would use their invitation as an endorsement by the Vatican of their work.

When asked whether Catholics would be confused when the Vatican invites people who do not support church teaching to speak at events, Father Borgman said, "I think it would be confusing to some." However, he added that it was more important for the church to be part of the debate and "have a voice."

Referring to the academy members who still opposed this approach, he said, "We cannot limit all of our actions to those that would be pleasing to others or we would never do anything. I think Peter would have gone back to fishing" if he were too concerned with meeting the approval of others.

Both Simon and Father Borgman said there would be a third congress on ethical stem-cell research, possibly next year.

Father Borgman said he was not sure who would be invited next time because it would depend on how the rapidly changing field develops.

This year's conference was to have looked at somatic cells and cord blood stem cells, he said, but by next year "perhaps there will be more pressing topics" or discoveries that need to be looked at.