Should laws in the United States allow stem cell research involving cloning?

Therapeutic cloning is the production of embryos for use in research and specifically for obtaining embryonic stem cells. Both Great Britain and South Korea permit some therapeutic cloning.

Fertility clinics can supply embryos created by IVF for use in stem cell research. But therapeutic cloning involves the capture of DNA from an individual for injection into an egg that had its original DNA removed. The resulting fertilized egg grows into an embryo, and the embryo provides the sought-after stem cells.

Human embryonic stem cells are the precursors to various types of cells in the human body. Human embryos are the source of these cells: after about a week of development, the embryo has a core of undifferentiated stem cells. Those stem cells can be removed before they began to differentiate.

Stem cells removed from the embryonic clone of a patient may be useful in the treatment of various diseases. Scientists are trying to learn how to influence the development of stem cells to produce the properly functioning cells needed by the individual. The most important effort in stem cell research aims at controlling the development of stem cells into particular types of tissue, among others, spinal cord, heart, brain tissues and tissues that produce hormones.

There are adult stem cells. The use of these does not generate the same kind of religious and political opposition that the use of embryonic stem cells does. But these cells are less malleable than the embryonic.