Stem Cell Research

Introduction

Stem cells are found in plants and animals, but most moral issues involve human stem cells. Such cells have two significant properties: (1) they can divide to form other types of cells and (2) they can divide indefinitely—that is, they are potentially “immortal.” There are three major types of stem cells. A totipotent stem cell can divide to form any kind of bodily cell, as well as an entire organism; an example is a fertilized egg (zygote). A pluripotent stem cell can divide to form many different kinds of bodily cells, such as neurons or heart cells. A multipotent stem cell can divide to form cells of a specific kind: Blood stem cells can form the various types of blood cells, such as red and white blood cells, but cannot divide to form liver or pancreatic cells (Eaton, 78).

Stem cells can be harvested from the adult (such as from bone marrow or brain tissue), from umbilical cord blood, from the placenta, and from embryos. Human embryonic stem cells (hES) are harvested from the inner cell mass of the embryo at the blastocyst stage, about 1 week after conception. The sources of embryos include aborted fetuses, but more often, spare embryos donated from fertility clinics. Stem cells can also be harvested from embryos made through cloning adult body cells.

Discussion and Analysis

Stem cell research is promising because stem cells could be used to grow replacements for damaged body cells, such as neurons to treat victims of spinal cord injury, Parkinson's disease, or Alzheimer's disease. Other possible diseases that could be treated include heart disease and diabetes. One day, entire organs may be grown.

There has been virtually no opposition on moral grounds to research on adult, umbilical cord blood, and placental stem cells (the placenta, which like the umbilical cord is part of the afterbirth, is a nutrient carrying organ joining the umbilical cord to the wall of the uterus). Stem cells from cord blood and the placenta are usually classified as adult stem cells. But many scientists believe that because embryonic stem cells, unlike adult stem cells, are naturally pluripotent, they could be used more effectively to grow many types of cells. In contrast to adult stem cell research, embryonic stem cell research has stirred a storm of controversy, with the lines of debate paralleling the abortion issue.

Embryonic cell that can develop into different tissues. Stem cells are used in medical research but their use is ethically controversial as the donor embryo is destroyed. Stem cells differ from other types of cells in that they are unspecialized cells that can reproduce themselves for long periods of time using cell division, but are capable of changing themselves into almost any type of specialist cell given the correct stimulus. Scientists have postulated that stem cell research could lead to cures for a wide range of medical conditions, from heart ailments to Parkinson's disease to growing replacement body parts (Holland, 33).

There are three basic kinds of stem cell, which are known as totipotent, ...