Archbishop Emeritus Carlos Quintero Arce of Hermosillo in Mexico encouraged the use of adult stem cells in medical research last week, underscoring that such a practice does not violate the right to life of embryos and respects the integrity of human life.

In a statement, the archbishop recalled that the use of embryonic stem cells raises “moral and ethical problems” because embryos are destroyed in the process. He then pointed to scientific studies which have shown that such cells are often rejected by the immune system when transplanted into patients.

In contrast, he continued, adult stem cells are often not rejected by the patient's immune system and they do not pose any ethical or moral issues. However, adult stem cells “do not proliferate in abundance and cannot be applied to all the cells of the body. For this reason, some scientists use embryonic stem cells more” despite the inconveniences.

For this reason, Archbishop Quintero praised the discoveries by Japanese scientist Shinya Yamanaka, who announced he had successfully reprogrammed ordinary cells from the tips of mouse tails to make them virtually indistinguishable from embryonic stem cells. He later carried out new re-programming experiments using human skin cells.

“American researcher James Thompson achieved similar results in cellular re-programming,” the archbishop noted, “and thus we can say that these studies are ‘the most significant step’ of our era.”

Archbishop Quintero expressed hope that the upcoming Second International Congress on Adult Stem Cells, organized by the Pontifical Academy for Life and the International Federation of Catholic Medical Associations, will further advance research with adult stem cells,” and thus “make us capable of effectively responding to the urgent therapeutic need that exists today.”