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Quick Facts

New downloadable PDF brochure Quick Facts on Stem Cell Research and Cloning for Catholics   


Q:  When does human life begin?

A:  Science is clear that a new distinct human organism is created at the moment of conception. The Catholic Church teaches that we must respect and protect human life from conception to natural death.


Q: What are stem cells?

A:  Stem cells are cells that are undifferentiated.  This means they have not yet committed to becoming a certain cell type, like a brain cell or a muscle cell.  There are several designations for stem cells.  Unipotent stem cells can only become one cell type.  Multipotent stem cells can become multiple cell types.  Pluripotent stem cells can become most or all of the over 200 cell types in the human body, and totipotent stem cells can become all cell types in the body, plus other tissue like placenta cells


Q:  Is there a difference between adult and embryonic stem cells?

A:  Yes.  Embryonic stem cells come from an embryo, 5-7 days after fertilization (the blastocyst stage).  Adult stem cells are abundant in umbilical cords, placentas, bone marrow, and several other tissues in the body.  These stem cells, although they do not need to come from adults, are referred to as “adult stem cells” to distinguish them from “embryonic stem cells".


Q:  Is stem cell research ethical?

A:  The answer is not a simple yes or no.  Research on stem cells, themselves, is not unethical, they are just cells.  Whether stem cell research is ethical depends on how the researchers got the stem cells.  Harvesting adult stem cells from umbilical cords or bone marrow does not require that the individual be destroyed.  For embryonic stem cells, this is not the case.  In order to harvest embryonic stem cells, the embryo must be destroyed. Any stem cell research that requires the destruction of human life is unethical.


Q:  Where do scientists get human embryos for research?

A: Scientists can get frozen embryos left-over from infertility treatments (IVF), they can create embryos with egg and sperm, or they can use somatic cell nuclear transfer (SCNT) to clone embryos.

Q:  Is it ethical to use embryos left-over from IVF for research since they will probably be discarded or die anyway?

A: No. It is never ethical to intentionally destroy an innocent human life even if it is for a proposed good.

Q:  Are embryonic stem cells currently providing treatments for disease?

A:  No. To date there have been no human trials using embryonic stem cells. Treatments from embryonic stem cells are decades away if they come at all.

Q:  Are there safety concerns about using embryonic stem cells for treatment of disease?

A: Yes. Embryonic stem cells have repeatedly caused tumors in animals. Some researchers question whether they will ever be safe to use in humans.


Q:  Are adult stem cells currently providing cures for disease?

A:  Yes.  Several stem cell therapies using a patient’s own stem cells are in trials or already in use.


Q:  Is human cloning ethical?

A:  No.  Cloning humans for any purpose is unethical.


Q:  Is a cloned embryo a human being?

A:  Yes.  A cloned human embryo is as much a human being as the person who is cloned.  A clone is a “delayed twin.”  The Church teaches that an embryo is a person no matter how that embryo was created.


Q:  What is somatic cell nuclear transfer (SCNT)?

A:   SCNT is cloning.  In SCNT, a technician takes an egg from a female donor, removes the nucleus, and inserts the somatic cell nucleus with its DNA into the “empty” egg.  SCNT is the transfer of the nucleus of a somatic cell to the egg.  The egg begins to divide and a cloned embryo is created.


Q:  Is there a difference between reproductive cloning and therapeutic cloning?

A:   No.  Both reproductive and therapeutic cloning would use SCNT to create a cloned embryo.  In reproductive cloning this cloned embryo is implanted into a uterus and allowed to develop into a child.  In therapeutic cloning, the embryo is destroyed for stem cells.


Q: Has anyone successfully cloned a human embryo with SCNT?

A:  Yes.  As of the this writing, researchers have been successful creating a few cloned human embryos with SCNT.


Q:  Is there a link between IVF and embryonic stem cell research and human cloning?

A:  Yes.  IVF clinics provide the “left-over” embryos to embryonic stem cell researchers.  They also provide human eggs for cloning.  If reproductive cloning becomes a reality, it will most likely be performed in an IVF clinic.

Q:  Is research on embryos legal in the U.S.?

A: Yes. There is no federal ban on creating or destroying human embryos for research. Scientists are free to conduct research on human embryos in most states. The Dickey Amendment restricts using federal tax-payer dollars to fund research that creates or destroys human embryos.

Q:  Is human cloning legal in the U.S.?

A: Yes. There is no federal ban on SCNT in humans. In most states, researchers are free to clone human embryos. The Dickey Amendment prohibits using federal tax-payer dollars to fund research that clones human embryos. 


Q:  What is genetic testing?

A:  Genetic testing is the testing of a person’s DNA.  Genetic testing is done for many reasons, including to establish paternity, diagnose disease, determine sex, or determine tissue type.  Scientists perform genetic testing on adults, children, fetuses, and, more recently, embryos in the very early stages of development. 


Q:  Is genetic testing ethical?

A:  Genetic testing simply provides information.  In and of itself, genetic testing is not unethical, unless human life is put at risk or destroyed to obtain that information.  The reason for the testing and what is done with the information provided are where the ethical dilemmas arise. 


Q:  What is genetic engineering?

A:  The manipulation of an organism's genome by introducing or eliminating specific genes through modern molecular biology techniques.  Genetic engineering in humans would include modifying DNA or adding an extra chromosome to a somatic cell nucleus before the cloning process so the resulting cloned embryo would be genetically modified.


Q:  Is the genetic engineering of plants and animals ethical?

A:  The genetic engineering of plants and animals is ethical if it is done in a responsible manner and done for the betterment of mankind, for example to provide a more abundant and nourishing food supply to the hungry.


Q:  Is the genetic engineering of humans ethical?

A:   If the genetic engineering is to treat or cure a disease, then yes.  This would be called "gene therapy."  If it is to make a normal healthy person, "better than human" with extra genes for strength, intelligence etc, than the answer is an emphatic "No!"  If genetic engineering requires the cloning or destruction of a human embryo than it is also unethical.