Stem cell image One day, stem cell research could treat and prevent an astounding array of ailments—from Parkinson’s and Alzheimer’s diseases to diabetes and cancer . But because of serious objections to the process of obtaining certain stem cells—a process that involves destroying 5- to 7-day-old human embryos—President Bush halted federal funding of most new stem cell research in 2001. Will treatments based on stem cell research ever make their way into our doctors’ offices? And should they?

Why Are Stem Cells Important?

Stem cells are unspecialized cells that can renew themselves for long periods of time, and when necessary, develop into any kind of cell in the human body. Scientists typically work with two types of stem cells:

  • Adult stem cells—In our bodies, adult stem cells stand ready to repair tissue when it is damaged by normal wear and tear or disease.
  • Embryonic stem cells—In embryos that are a few days old, embryonic stem cells give rise to all the different cells of the human body.

Researchers have also discovered other sources of stem cells—embryonic germ cells and amniotic fluid stem cells.

Why Are Scientists Excited About Embryonic Stem Cells?

Scientists believe that embryonic stem cells offer enormous medical and scientific potential. In the future, embryonic stem cells could be used to:

Replace Diseased Cells

If scientists can direct stem cells’ specialization process, they may be able to use embryonic stem cells to treat a wide range of ailments. For example, Parkinson’s disease is a common disorder marked by tremors and loss of muscle control. It is caused by the loss of certain brain cells. Stem cells could be used to replace those lost cells. In fact, Parkinson’s disease may be one of the first diseases treatable by stem cell transplantation. Early studies confirm that stem cells can be directed to produce the cells needed by Parkinson’s patients.

Stem cells may also be used in the treatment of Type 1 diabetes . Patients suffering from this kind of diabetes have difficulty producing insulin from pancreas cells. Using stem cell transplantation, doctors could someday offer diabetes patients new insulin-forming cells, eliminating the need for insulin injections.

Stem cells could also be used in the treatment of conditions such as Alzheimer’s disease, spinal cord injuries, liver disease, arthritis , and hair loss.

Better Understand Human Biology

Understanding how humans develop into tremendously complex creatures will help scientists correct “errors” that can happen during this process—for example, cancer or birth defects.

Create Tissue for Medical Therapies

Today, organ transplants give people suffering from certain diseases a new life. But organ donors are in short supply. One day, scientists may be able to use embryonic stem cells to help repair damaged organs or even grow a new organ.

What Are the Ethical and Legal Concerns?

No one argues about the promise of embryonic stem cell research. But embryonic stem cells are currently most often derived from 5- to 7-day-old embryos. The embryos are created outside of a woman’s body (“ in vitro ”) for reproductive purposes and are donated for research when no longer needed. Gathering embryonic stem cells destroys the embryo, a process which some believe is killing a person.

When does life begin? Do human embryos have legal rights? Though not unique to the stem cell debate, these are serious ethical and legal questions that must be addressed.

Why Can’t Scientists Just Use Adult Stem Cells?

Currently, adult stem cell use is limited for several reasons. Adult stem cells exist in very small quantities in the body and are difficult to isolate. Adult stem cells may not have the same capacity as embryonic stem cells to multiply in the laboratory, and they may only be able to develop into certain kinds of tissues. So scientists are very interested in investigating embryonic stem cells. While initial reports suggested that adult stem cells might be useful in certain treatments, such as helping the heart recover better after a heart attack , more recent studies have not provided strong evidence for benefit. It remains to be seen whether embryonic stem cells could perform better.

Are Stem Cells Used in Current Treatments?

Stem cell research is a very new area, even though doctors have used stem cells in bone marrow transplants for more than 30 years to help treat certain cancers. Scientists have only been working with embryonic stem cells since 1998. Both adult and embryonic stem cell research still pose many unanswered questions. It will be years before stem cell treatments are widely available.

What Is the Future for Stem Cell Research?

President Bush’s stem cell policy allows federal funding for research with stem cell “lines” (cells that can be grown in the laboratory) created before August 2001. The policy prohibits scientists from creating new lines.

Critics claim that President Bush’s stem cell policy impedes life-saving research and allows private companies—who are under no obligation to publicize research results—to dominate the field. Others believe that the policy encourages “embryo farming” and weakens respect for early life.

In the meantime, some researchers have secured private funding to finance their embryonic stem cell research. In addition, stem cell research can be founded by individual states with state money if appropriate state laws are established.

Ongoing public debate is needed to resolve these issues. Until then, stem cell research offers many promises and many questions.