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Common Questions About Stem Cell Research

There are a lot of myths about stem cell research, the origin of the stem cells themselves, and the type of work that takes place. Learn what really takes place in stem cell research.

How does CIRM ensure that the work it funds is carried out ethically?

Stem cell research, like any biomedical research, poses social and ethical concerns that CIRM, and the broader research community, takes very seriously. The research community has a history of addressing ethical challenges, and dealing with them in ways that allow research to move forward responsibly.

State and national funding bodies, such as CIRM and the NIH, have comprehensive policies to govern research. For example, CIRM-funded researchers must comply with a comprehensive set of regulations that have been carefully developed and are in accordance with national and international standards. These regulations were among the first formal policies governing the conduct of stem cell research and are in accordance with recommendations from the National Academies and from the International Society for Stem Cell Research. CIRM’s Standards Working Group meets regularly to consider new ethical challenges as the science progresses and to revise standards to reflect the current state of the research.

Where do the embryos come from to create stem cell lines?

All the human embryonic stem cell lines currently in use come from four to five day old embryos left over from in vitro fertilization (IVF). These embryos are smaller than the size of the dot over an “i”, and consist of a hollow ball of roughly 100 cells. In inner cluster of 20 or so cells, called the inner cell mass, are the source of the embryonic stem cells.

The IVF embryos may be leftovers after a couple has completed their family. Other embryos might be ones the couple chose not to implant due to genetic mutations. Still other embryos might be malformed in some way that causes them to be rejected for implantation into the mother. Thousands of these embryos are discarded every year.

It is important to note that cells with the potential to form embryonic stem cells in a lab dish only exist in these very young, four to five day old blastocysts. They are a fleeting cell type that disappears after that point in time. A common misconception is that the cells can come from older embryos or from aborted fetuses, which is in fact not possible.

Where do human eggs come from for creating new stem cell lines?

The process of SCNT requires human eggs from living donors. There are a wide range of national and international policies regarding human egg donation. All policies require voluntary and informed consent from the women so they understand the risks and benefits of egg donation. 

Policies vary as to whether women may be paid or otherwise compensated to donate eggs.  Most jurisdictions allow donors to be reimbursed for direct costs such as travel to the clinic or lodging.  Some also allow payments or IVF services to be provided to egg donors. Read CIRM’s policies on egg donation.

What other options do people have for unused embyos from fertility treatments?

People who undergo IVF and have stored embryos have several options regarding what to do with the excess embryos once they have completed their family.

  • They can simply discard the embryos 
  • They can store the embryos indefinitely at their own expense
  • They can give the embryos to other infertile couples. So far only ~200 children have been born from donated IVF embryos.
  • They can donate the embryos to general research or stem cell research

People who donate their left over embryos for research go through an extensive consenting process to ensure that they understand embryonic stem cell research. Under California state, national, or international regulations, no human embryonic stem cell lines should be created without explicit consent from the couple.

If adult stem cells can be used to treat disease why work with embryonic stem cells?

Adult stem cells are extremely valuable and have great potential for future therapies. However, these cells are very restricted in what they can do. Blood forming stem cells can treat some blood diseases, and brain stem cells may be able to treat some neural diseases, but those cells can’t turn into other tissues types. What’s more, adult stem cells don’t grow indefinitely in the lab, unlike embryonic stem cells, and they aren’t as flexible in the types of diseases they can treat.

Embryonic stem cells also have the advantage of revealing what takes place at the earliest stages of development, when some diseases develop. Only by studying those earliest steps can researchers understand how the diseases form and therefore understand how to develop treatments.

CIRM encourages work with adult stem cells and is excited about their potential for treating some diseases. However, the goal of CIRM is to accelerate new treatments for incurable diseases and at this time the most effective way of doing that is by exploring all types of stem cells: adult, embryonic, and iPS.

Don't iPS cells eliminate the need to use embryos in stem cell research?

iPS cells generated from adult human tissues are a very exciting advance, which is why CIRM has funded many grants exploring new ways of creating and using these cells to study or treat disease. However, currently the only way to make iPS cells involves introducing potentially cancer-causing genes into the DNA. The cells can’t be used in therapies if they have the potential to cause cancer. What’s more, the technology to create iPS cells is very new and it is still not known whether those cells have the same potential as human embryonic stem cells.

Researchers are working to find better ways of creating iPS cells that are safe and avoid dangerous virus or mutation so the cells can be used therapeutically. In the mean time, waiting for iPS cells to become therapeutically safe – which will likely take many years – would slow the search for disease treatments. Cures can’t wait.

Experts agree that research on all types of stem cells is critical.  In September 2008, a panel of experts convened by the U.S. National Academy of Sciences agreed that the use of human embryonic stem cells is still necessary.  As the expert panel, chaired by Richard Hynes of the Massachusetts Institute of Technology stated “It is far from clear at this point which types of cell types will prove to be the most useful for regenerative medicine, and it is likely that each will have some utility.

Can the embryos created for stem cell research be used for reproductive cloning?

No. Every significant regulatory and advisory body has restrictions on reproductive cloning. The National Academy of Sciences has issued guidelines banning the technique as has the International Society for Stem Cell Research. CIRM regulations specifically prohibit reproductive cloning with its funding.