The following comes from a February 6 Crux article by John L. Allen Jr. A previous CalCatholic article, Pope Francis said to bless human-animal chimeras, was published January 28.

In a recent interview with Scientific American, a Spanish biologist named Juan Carlos Izpisua Belmonte at the California-based Salk Institute claimed that Pope Francis had given an ethical thumbs-up to research on animal/human genetic hybrids.

After that report made the rounds, the Vatican issued a swift denial: “It’s absolutely unfounded that Pope Francis has pronounced himself with an encouragement for this type of research,” the Rev. Federico Lombardi told the Italian news outlet Il Sismografo.

One of Catholicism’s leading experts on bioethics now says it was always implausible the pope would sign off on animal/human hybrids, called “chimeras,” in such a sweeping fashion, because “there’s no way to give blanket approval for something like this … it has to be looked at on a case-by-case, proposal-by-proposal basis.”

The Rev. Tad Pacholczyk, director of education for the Philadelphia-based National Catholic Bioethics Center, told Crux Thursday that when it comes to the ethics of mixing materials between humans and animals, “the devil is always in the details.”

The type of research Izpisua is proposing involves implanting human cells into embryonic pigs and other farm animals in order to grow human hearts, kidneys, and other organs, primarily to alleviate the donor shortage for organ transplants.

The aim is to induce one species to grow an organ of the other, not a combination of two species.

In principle, he said, the research that biologists such as Izpisua are pursuing could pass ethical muster if three conditions are satisfied:

• The procedures must not involve the creation or destruction of human embryos.
• They must not involve the replication of major pillars of human identity in animals, such as the brain system.
• They must not involve the production of human gametes, meaning the basic building blocks of human reproduction.

Assuming that’s the case, he said, and that technical challenges can be worked out – for instance, avoiding the risk of transferring diseases from one species to the other – then in principle, the Church likely would not object.

“We use animals for a wide panoply of purposes,” Pacholczyk said. “We eat them, we use them to make clothing, we use them for basic scientific research … so if we can use them to produce organs to save people’s lives without crossing fundamental ethical lines, presumably it would be morally non-problematic.”