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A stem cell is a relatively unspecialized cell that, when it divides, can either make another cell like itself, or make any of a number of cells with more specialized functions.  The Catholic Church is not opposed to all types of stem cell research.  Most stem cell research uses cells obtained from adult tissue, umbilical cord blood, and other sources that pose no moral problem.  Useful stem cells have been found in bone marrow, blood, muscle, fat, nerves, and even in the pulp of baby  teeth. Some of these cells are already being used to treat people with a wide variety of diseases.

The Church opposes embryonic stem cell research because harvesting these stem cells kills a living human embryo. The Church opposes the direct destruction of innocent human life for any purpose, including research.

Facts & Figures

  • "I human embryonic stem cell research does not make you at least a little bit uncomfortable, you have not thought about it enough. I thought long and hard about whether I would do it.” This is a quote from James Thomson, the first to derive a human embryonic stem cell line in 1998.(1)

  • Proposition 71 in California provide $3 billion over 10 years for state funded (embryonic) stem cell research. Twenty-five years have gone by, and there are “no cures and therapies based on hESCs [human embryonic stem cells]”.(2)

  • Besides moral issues with human embryonic stem cell research, the studies have not been successful due to the nature of embryonic stem cells and how they act, plus getting them where they need to go even if scientists are able to develop them into the type of cells they would like to make.(3)

​Below is an ethical overview of some of the current types of stem cell research:

  • Embryonic Stem Cells (pluripotent stem cells harvested from living embryos which are 3-5 days old) — always morally objectionable, because a young human must be destroyed in order to harvest his or her stem cells

  • Embryonic Germ Cells (pluripotent stem cells derived from germ cells [sperm or egg-producing cells] of fetuses) — morally objectionable when utilizing cells derived from elective abortions, but morally acceptable when utilizing cells from spontaneous abortions (miscarriages) if the parents give informed consent

  • Adult Germ Cells (pluripotent stem cells derived from testicular biopsy) – morally acceptable, assuming informed consent of the adult donor

  • Umbilical Cord Stem Cells — morally acceptable, since the umbilical cord is no longer required once a baby has been delivered

  • Placentally-derived Stem Cells — morally acceptable, since the afterbirth is no longer required once a baby has been delivered

  • Post-Natally Derived (Adult) Stem Cells (e.g. stem cells from bone marrow or blood or fat from liposuction) — morally acceptable, assuming informed consent from the adult donor

  • De-Differentiation Strategies (pluripotent stem cells derived from treating adult cells with chemicals or other bio-active substances to “back-differentiate” them towards a more primitive state) — morally acceptable as long as the de-differentiation procedure doesn’t go so far as to make a human embryo

  • Reprogramming Strategies (pluripotent stem cells derived using a modified nuclear transfer technique, for example ANT-OAR) — morally acceptable as long as the reprogramming generates a distinctly non-embryonic entity, that is to say, a cell or group of cells that is not an organism, from which stem cells could be obtained.




Church Documents

Catechism of the Catholic Church

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