Frequently Asked Questions
What are "stem cells"?
What is a "stem cell line"?
Are all stem cells the same?
What are "adult" stem cells?
What are "embryonic" stem cells?
Can we find cures solely through the use of adult stem cells?
Where do embryos that are used for embryonic stem cell research come from?
Why is stem cell research important?
If stem cell research has been going on for over 40 years, why is the issue getting so much focus right now?
What is an example of a stem cell treatment?
For which specific ailments might stem cell research provide treatments or cures?
What is somatic cell nuclear transfer?
Why is embryonic stem cell research confused with human (or reproductive) cloning?
Does Americans for Cures Foundation support cloning?
Does the federal government support stem cell research?
If more stem cell lines were made available, would treatments and cures be developed soon, or would it take many years?
Researchers have described techniques for getting embryonic stem cells without destroying embryos. Does this end the debate over embryonic stem cell research?
What are "stem cells"?
Stem cells are the "building blocks" of living beings. They exist at the earliest stages of development and grow into all of the cell types in the body. Stem cells have two unique qualities: 1) they can copy themselves, and 2) they can grow into different cell types. When a stem cell copies itself, each of the two new cells can either remain a stem cell or become another type of cell such as a muscle cell, blood cell, or brain cell.
While some stem cells grow into organs, bones and tissues of the body, other stem cells work in the immune and repair systems. These cells, called "adult" stem cells, create replacement cells for those that are lost through injury, disease or the normal wear and tear of aging.
What is a "stem cell line"?
A stem cell line, also called an embryonic stem cell line, refers to all cells that were created from a single stem cell. Similar to the way that family members can be traced back to one common ancestor, stem cells can be traced back to one original stem cell. These cells are then said to be one "cell line." Cell lines can include many millions of identical cells and these cells are thought to be able to divide and exist forever.
Are all stem cells the same?
No, there are different types of stem cells with different characteristics and abilities. The two most commonly referred to are "adult" and "embryonic" stem cells.
What are "adult" stem cells?
Adult stem cells are stem cells that have already started to develop into a particular cell type. These stem cells are found in adult tissue and also in other fully developed tissue. For example, the stem cells found in the umbilical cord during and shortly after delivery are considered adult stem cells because they have already partially developed into blood cells.
Adult stem cells replenish the tissues where they are found, such as new skin that develops when a wound heals. They are able to renew themselves and are considered "multipotent," meaning they can sometimes turn into several different kinds of cells within the same basic cell type. For instance, adult stem cells found in bone marrow can turn into all of the different types of cells found in blood.
Research on adult stem cells has been funded for over 40 years and several successful therapies have been developed. But scientists believe that, because of their versatility, the potential of embryonic stem cells is even greater than adult stem cells.
What are "embryonic" stem cells?
Embryonic stem cells are blank, unspecialized cells found in a blastocyst. A blastocyst is a mass of 150 or so cells that is smaller than the period at the end of this sentence. It develops approximately 5-14 days after an egg is fertilized. Embryonic stem cells make up the inner cell mass of the blastocyst.
Unlike adult stem cells, embryonic stem cells are "pluripotent." These means they have the ability to grow into any and every cell in the body, with the exception of egg and sperm cells. They also have the ability to continue to multiply and exist indefinitely.
Embryonic stem cells, also known as "Human embryonic stem cells" (HeSC), were first discovered in 1998. To date, research on them has not been well funded. But scientists believe that their versatility gives embryonic stem cells even greater potential than that of adult stem cells.
Can we find cures solely through the use of adult stem cells?
Adult stem cells are used to treat some types of disease, including leukemia and other blood diseases. We believe that scientists should study adult stem cells in areas where they show promise. However, most of the nation's top scientists and institutions agree that embryonic stem cells are more likely to treat a wide range of diseases and injuries.
Also, stem cell based treatments will require many cells that are safe, stable and identical. Adult stem cells do not exist in large numbers and so aren't available to treat the millions of people living with disease. To create as many cells as we will need, scientists must direct stem cells to divide many, many times. Adult stem cells can not divide over time and create stable cells. It is extremely hard to isolate and grow adult cells in the lab. Scientists believe embryonic stem cells are the only realistic supply for practical cell based therapies.
Where do embryos that are used for embryonic stem cell research come from?
Most embryonic stem cells currently used for research come from fertility clinics. Infertile couples seeking to have a child through in vitro fertilization often have multiple embryos frozen and stored at fertility clinics. When the extra embryos are no longer needed, they are usually thrown away. As an alternative to having them discarded, couples can donate them for research.
In 2003, it was reported that U.S. fertility clinics were storing about 400,000 frozen embryos. Yet in 2001, President Bush restricted federal money to embryonic stem cell lines that already existed. Estimated to be about 78 at that time, the number of viable stem cell lines available is now thought to be only 22.
Egg donation also offers a means through which embryonic stem cells can be made available for research (see somatic cell nuclear transfer). While not supported by federal funding, some state initiatives, like the one passed in California in 2004, will support this process. Strict guidelines are being put in place to ensure that the donation process is conducted as safely and ethically as possible.
Why is stem cell research important?
Leading scientists agree that stem cell research has great life-saving potential and could revolutionize how diseases and injuries are studied and treated.
Learning how stem cells grow into the different cell types in the body is helping scientists to better understand normal and abnormal development. Creating stem cell lines can even show them how a particular disease develops, and allow them to test new therapies on human cells. By testing therapies on human cells before testing them on living people, scientists can make sure that therapies are safe and effective. This could reduce the risk of clinical trials and shorten the time it takes to get therapies to patients.
If stem cell research has been going on for over 40 years, why is the issue getting so much focus right now?
Adult stem cell research has been going on for decades, and has been widely supported by federal funding in the United States. However, embryonic stem cells were just discovered in 1998. Since researchers believe it has such tremendous potential for finding more effective treatment and even cures for over 70 serious diseases and injuries, embryonic stem cell research has become a major focus of research around the world. But because of strong restrictions on federal funding imposed by the current administration, the United States has lagged behind. To make up for this, and help the U.S. become a leader in this important field, states such as California, New Jersey, and others are working to increase local support of this vital area of research.
What is an example of a stem cell treatment?
Stem cells could be used to replace damaged cells in chronic disease and injury. For example, bone marrow contains adult stem cells that grow into blood cells to replace those that have died. The average red blood cell only lives 90 days before it is replaced by our bodies. Doctors transplant bone marrow to treat leukemia (blood cancer) and other blood diseases. This bone marrow can then provide the supply of new healthy blood.
For which specific ailments might stem cell research provide treatments or cures?
There are over 70 diseases and injuries that could be helped by stem cell research. Some of the diseases that could be helped include Parkinson's disease, Alzheimer's, spinal cord injury, stroke, heart disease, diabetes, arthritis and even severe burns.
What is somatic cell nuclear transfer?
A research process called somatic cell nuclear transfer (SCNT), sometimes referred to as “nuclear transfer” or "therapeutic cloning", allows scientists to copy cells so that their genetic material, or DNA, matches exactly. Scientists remove the nucleus (containing the DNA) from an unfertilized egg and replace it with the nucleus (containing the DNA) from the cell of a patient who has a disease. The egg, with the new genetic material, is stimulated to convert to a blastocyst which contains stem cells that match the patient and has their disease. In this process, there is no sperm, no implantation in a uterus and no pregnancy.
SCNT offers scientists a unique way to learn about diseases and test new therapies on human cells. By testing therapies on human cells before testing them on living people, scientists can make therapies more safe and effective. This could also reduce the risk of clinical trials and the time it takes to get therapies to patients.
Why is embryonic stem cell research confused with human (or reproductive) cloning?
Cloning is when cells are copied so that their genetic material, or DNA, matches exactly.
Embryonic stem cell research utilizes a process called therapeutic cloning, or somatic cell nuclear transfer (SCNT), to copy cells with the goal of making stem cells to better treat and cure people with serious diseases and injuries. Using SCNT, scientists can produce embryonic stem cells without using sperm to fertilize an egg. In this process, there is no implantation in a uterus and therefore no pregnancy.
Reproductive cloning copies cells with the goal of making a cloned living being (i.e. human, animal). This type of cloning uses an egg which is stimulated to convert to a blastocyst and then implanted in a uterus. Nearly all scientists and physicians agree that human reproductive cloning is unethical and should not be done. In California and many other states, it is illegal to clone a human being.
Does Americans for Cures Foundation support cloning?
Americans for Cures is against human reproductive cloning and believes that there should be a complete ban on it.
We believe that scientists must, however, be allowed to use SCNT. This is perhaps the best hope for finding treatments and cures for people with a wide range of serious diseases and injuries.
Does the federal government support stem cell research?
The government funds adult stem cell research, which has far less promise than embryonic stem cell research. However, limited federal funding is available for embryonic stem cell research. President Bush declared that federal money could only be used to study stem cell lines that existed as of August 9, 2001. There are several problems with this:
There are only 22 lines that qualify for this and less than twelve of these are easily available to scientists.
These cell lines are not diverse. They are derived from embryos of a certain profile of individuals (typically of similar ethnicity, educational background, income level, etc.) Diversity in the cells would help scientists better understand and treat many more diseases and individuals than they can with these limited cell lines.
These cell lines got their nutrients from animal cells and will never be safe to use in treatments for people.
Some of these cell lines aren't stable enough to be used in experiments.
The lack of resources available to U.S. scientists has caused many leaders in the field to move to other countries, where much more funding is available for this important area of research. It has also greatly limited the number of bright young scientists choosing to focus their careers on stem cell research.
If more stem cell lines were made available, would treatments and cures be developed soon, or would it take many years?
It is impossible to know how fast scientists will find new treatments and cures. A significant breakthrough is usually reached as a result of many smaller breakthroughs, each of which takes time to identify, develop and test. But it is known that giving scientists access to the tools they need (i.e. stem cell lines) will make them much more effective and will allow their work to move along more quickly.
There are also many other factors that can affect how fast new treatments and cures are found. They include how much money is available to fund the research, how many scientists know how to do the research, and the general political environment.
Every day that these factors are allowed to stall stem cell research is one more day that millions of individuals and families will have to wait to get closer to a healthier future.
Researchers have described techniques for getting embryonic stem cells without destroying embryos. Does this end the debate over embryonic stem cell research?
Not any time soon. It is true that teams of scientists have created two new ways to produce embryonic stem cells. Yet, their experiments were done in mice and each method raises practical and ethical issues of its own. Neither is likely to be ready for use in humans for many years.
We believe that scientists should keep looking for new ways to create stem cells without destroying embryos. They must not, however, be forced to stop or slow the most proven way to get embryonic stem cells - a way that is supported by a clear majority of Americans. To do that would result in losing critical progress in the fight against diseases and injuries threatening millions of lives.
For definitions of the key terms used here, please visit our Glossary. Go to Stem Cell Facts to get more important information about stem cell research.
