What are stem cells?
When the human body is embryonic, it contains "stem" cells that are capable of developing into any kind of tissue--heart muscle, blood, brain cells, and so on. If stem cells could be artificially controlled, they might be used to create fresh, healthy tissue that may be able to cure Parkinson's disease, Alzheimer's, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, and rheumatoid arthritis.
Scientists have recently learned how to cause human stem cells to reproduce themselves, which is the first step to their use as a cure. No stem-cell cure exists at the moment, however. Researchers project it will be five to 10 years until the first stem-cell-based therapy becomes available. Some stem-cell therapies are already working in mice, which is encouraging, but not a guarantee they will work in people.
Why is stem-cell research controversial?
So far, the only way to obtain stem cells for research is to take them from aborted fetuses or from embryos discarded by fertility clinics. Researchers who work from aborted fetuses use only those from the early first trimester, and which would have been aborted regardless. (Both artificially aborted and naturally miscarried fetuses can be used.) Most opponents of abortion also oppose any research use of aborted fetuses. Most stem-cell researchers prefer to work with discarded embryos from fertility clinics. Use of such embryos is opposed by the Catholic Church and by some, but not all, pro-life organizations.
It's legal to do research on human embryos?
Under current rules, federally funded researchers cannot use aborted fetuses under essentially any condition and can use discarded embryos only if federal funds had nothing to do with the creation of the embryo. Privately funded fertility clinics are essentially unregulated and can do almost anything with embryonic material, including attempt to clone human beings.
The practical effect of the current legal situation is that private fertility clinics do whatever they wish; mainly, they create and store embryos to help couples with fertility problems. A few private research companies, prominently Geron, study stem cells derived from discarded embryos. A few major-university researchers study stem cells from aborted fetuses but use only private funds for their work. A few federally funded researchers study stem cells from discarded embryos. It is assumed that if federal rules on stem cells were liberalized, many more researchers would study them.
What must President Bush decide?
In 2000, President Clinton proposed a rule that would moderately liberalize stem-cell study, clarifying regulations to confirm that federally funded researchers may work with stem cells derived from unwanted embryos, so long as no federal funds are involved in the creation of the embryo. Bush must decide whether to uphold or overturn this rule.
Is there a way to get stem cells without a moral quandary?
Several laboratories are working on taking mature cells from adults and chemically "tricking" them into turning back into the stem cells they once were. Until recently, biologists thought that reversing the direction of cell "differentiation" would be impossible, but now it looks like they were wrong. If successful, the adult-derived technique would allow the reproduction of stem cells without the use of aborted fetuses or discarded embryos. Whether this will work is unknown at the moment; initial tests have yielded mixed results. And even if successful, adult-derived stem cells may not resolve all moral issues. Once "tricked" into reverting to their earlier state, adult-derived stem cells become what are essentially new embryos that would be clones of the person from which the sample cell is extracted.